Git: Preserve reviewers list in GerritPushDialog

Not stored in settings (it is not important enough), but usually
the same reviewers are required for consequent changes

Change-Id: I28564791419ac441478db65e51b09189b9f2f196
Reviewed-by: Petar Perisin <petar.perisin@gmail.com>
Reviewed-by: Tobias Hunger <tobias.hunger@digia.com>

src/plugins/git/gerrit/gerritplugin.h

@@ -89,6 +89,7 @@ private:
     QSharedPointer<GerritParameters> m_parameters;
     QPointer<GerritDialog> m_dialog;
     ActionCommandPair m_pushToGerritPair;
+    QString m_reviewers;
 };
 
 } // namespace Internal