IDEA-69855 NPE Timer might have been not initialized yet. [Reviewed by irengrig]

plugins/git4idea/src/git4idea/commands/GitTask.java

@@ -373,7 +373,9 @@ public class GitTask {
     }
 
     public void dispose() {
-      myTimer.cancel();
+      if (myTimer != null) {
+        myTimer.cancel();
+      }
     }
   }