Inline edit: Strip trailing blank lines from commit messages

Trim the input commit message to prevent trailing blank lines. If
blank lines are present, it causes problems when the commit is
merged and then cherry-picked with the -x option (from the command
line).

Trim it both on the client and on the server.  If we do it only on
the client, it will still be possible to update the commit message
with trailing blank lines by a direct call to the REST API.

Bug: Issue 3616
Change-Id: I1a3df4668d7ba6f395c5e782e2962652ead577d8

gerrit-gwtui/src/main/java/com/google/gerrit/client/editor/EditScreen.java

@@ -453,6 +453,13 @@ public class EditScreen extends Screen {
         if (!cm.isClean(generation)) {
           close.setEnabled(false);
           String text = cm.getValue();
+          if (Patch.COMMIT_MSG.equals(path)) {
+            String trimmed = text.trim() + "\r";
+            if (!trimmed.equals(text)) {
+              text = trimmed;
+              cm.setValue(text);
+            }
+          }
           final int g = cm.changeGeneration(false);
           ChangeEditApi.put(revision.getParentKey().get(), path, text,
               new GerritCallback<VoidResult>() {