Clean headers in Git.

Ran script to remove inludes on a trial-and-error basis and
manually corrected it.

Change-Id: Ib2afbc530760684db96888b927c5153b29fe24aa
Reviewed-by: Tobias Hunger <tobias.hunger@digia.com>

src/plugins/git/gerrit/gerritpushdialog.cpp

@@ -32,10 +32,8 @@
 
 #include "../gitplugin.h"
 #include "../gitclient.h"
-#include <coreplugin/icore.h>
 
 #include <QDir>
-#include <QMessageBox>
 
 namespace Gerrit {
 namespace Internal {