memory: do not store millions of duplicate strings

platform/vcs-log/impl/src/com/intellij/vcs/log/impl/VcsCommitMetadataImpl.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2014 JetBrains s.r.o.
+ * Copyright 2000-2016 JetBrains s.r.o.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -31,7 +31,7 @@ public class VcsCommitMetadataImpl extends VcsShortCommitDetailsImpl implements
                                @NotNull String subject, @NotNull VcsUser author, @NotNull String message,
                                @NotNull VcsUser committer, long authorTime) {
     super(hash, parents, commitTime, root, subject, author, committer, authorTime);
-    myFullMessage = message;
+    myFullMessage = message.equals(getSubject()) ? getSubject() : message;
   }
 
   @Override