ConcurrentModificationException in v1.0
Upgraded from v0.9 to 1.0 a few moments ago.
After restarting (and every subsequent restart) Webstorm (v9.0.3), I receive a "ConcurrentModificationException: null" in the Event Log.

Error details:

```
Exception in plugin .ignore

null
java.util.ConcurrentModificationException
    at java.util.HashMap$HashIterator.nextEntry(HashMap.java:793)
    at java.util.HashMap$KeyIterator.next(HashMap.java:828)
    at mobi.hsz.idea.gitignore.IgnoreManager$IgnoreCacheMap.isFileIgnored(IgnoreManager.java:345)
    at mobi.hsz.idea.gitignore.IgnoreManager.isFileIgnored(IgnoreManager.java:213)
    at mobi.hsz.idea.gitignore.vcs.IgnoreFileStatusProvider.getFileStatus(IgnoreFileStatusProvider.java:68)
    at com.intellij.openapi.vcs.impl.FileStatusManagerImpl.calcStatus(FileStatusManagerImpl.java:133)
    at com.intellij.openapi.vcs.impl.FileStatusManagerImpl.getStatus(FileStatusManagerImpl.java:268)
    at com.intellij.ide.projectView.impl.nodes.AbstractPsiBasedNode.getFileStatus(AbstractPsiBasedNode.java:115)
    at com.intellij.ide.util.treeView.AbstractTreeNode.setForcedForeground(AbstractTreeNode.java:85)
    at com.intellij.ide.util.treeView.AbstractTreeNode.postprocess(AbstractTreeNode.java:77)
    at com.intellij.ide.util.treeView.PresentableNodeDescriptor.getUpdatedPresentation(PresentableNodeDescriptor.java:91)
    at com.intellij.ide.util.treeView.PresentableNodeDescriptor.update(PresentableNodeDescriptor.java:41)
    at com.intellij.ide.util.treeView.AbstractTreeBuilder.updateNodeDescriptor(AbstractTreeBuilder.java:594)
    at com.intellij.ide.util.treeView.AbstractTreeUi$22.run(AbstractTreeUi.java:944)
    at com.intellij.ide.util.treeView.AbstractTreeUi.execute(AbstractTreeUi.java:1830)
    at com.intellij.ide.util.treeView.AbstractTreeUi.update(AbstractTreeUi.java:940)
    at com.intellij.ide.util.treeView.AbstractTreeUi.update(AbstractTreeUi.java:892)
    at com.intellij.ide.util.treeView.AbstractTreeUi.collectNodesToInsert(AbstractTreeUi.java:2256)
    at com.intellij.ide.util.treeView.AbstractTreeUi.access$4500(AbstractTreeUi.java:62)
    at com.intellij.ide.util.treeView.AbstractTreeUi$30.run(AbstractTreeUi.java:1399)
    at com.intellij.openapi.util.ExecutionCallback.setExecuted(ExecutionCallback.java:59)
    at com.intellij.openapi.util.ActionCallback.setDone(ActionCallback.java:69)
    at com.intellij.openapi.util.ActionCallback$3.run(ActionCallback.java:233)
    at com.intellij.openapi.util.ExecutionCallback.doWhenExecuted(ExecutionCallback.java:101)
    at com.intellij.openapi.util.ActionCallback.doWhenDone(ActionCallback.java:108)
    at com.intellij.openapi.util.ActionCallback.notify(ActionCallback.java:153)
    at com.intellij.ide.util.treeView.AbstractTreeUi$34.run(AbstractTreeUi.java:1783)
    at com.intellij.ide.util.treeView.AbstractTreeUi.executeYieldingRequest(AbstractTreeUi.java:2091)
    at com.intellij.ide.util.treeView.AbstractTreeUi.access$5900(AbstractTreeUi.java:62)
    at com.intellij.ide.util.treeView.AbstractTreeUi$38$1.run(AbstractTreeUi.java:1983)
    at com.intellij.ide.util.treeView.AbstractTreeBuilder.runOnYeildingDone(AbstractTreeBuilder.java:439)
    at com.intellij.ide.util.treeView.AbstractTreeUi.runOnYieldingDone(AbstractTreeUi.java:2186)
    at com.intellij.ide.util.treeView.AbstractTreeUi$38.run(AbstractTreeUi.java:1978)
    at com.intellij.ide.util.treeView.AbstractTreeBuilder$1.process(AbstractTreeBuilder.java:53)
    at com.intellij.ide.util.treeView.AbstractTreeBuilder$1.process(AbstractTreeBuilder.java:50)
    at com.intellij.util.containers.TransferToEDTQueue.processNext(TransferToEDTQueue.java:97)
    at com.intellij.util.containers.TransferToEDTQueue.access$300(TransferToEDTQueue.java:35)
    at com.intellij.util.containers.TransferToEDTQueue$1.run(TransferToEDTQueue.java:56)
    at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:715)
    at java.awt.EventQueue.access$400(EventQueue.java:82)
    at java.awt.EventQueue$2.run(EventQueue.java:676)
    at java.awt.EventQueue$2.run(EventQueue.java:674)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:86)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:685)
    at com.intellij.ide.IdeEventQueue.e(IdeEventQueue.java:748)
    at com.intellij.ide.IdeEventQueue._dispatchEvent(IdeEventQueue.java:577)
    at com.intellij.ide.IdeEventQueue.dispatchEvent(IdeEventQueue.java:384)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:296)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:211)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:201)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:196)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:188)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)
```
