Allow the text of the "Report Bug" link to be configured

The title text shown on the link to the bug tracker can be configured
in the gerrit.config file.  If not set, it defaults to "Report Bug".

Bug: Issue 2318
Change-Id: I38c6057b96bf97fc96341621c9d8bbb49060dc40

gerrit-gwtui/src/main/java/com/google/gerrit/client/Gerrit.java

@@ -464,8 +464,9 @@ public class Gerrit implements EntryPoint {
     btmmenu.add(new InlineLabel(" | "));
     btmmenu.add(new InlineHTML(M.poweredBy(vs)));
 
+    final String reportBugText = getConfig().getReportBugText();
     Anchor a = new Anchor(
-        C.reportBug(),
+        reportBugText == null ? C.reportBug() : reportBugText,
         getConfig().getReportBugUrl());
     a.setTarget("_blank");
     a.setStyleName("");