Clean headers of the DiffEditor plugin.

Change-Id: I1c49527f010acbece31849127fc4d182678b6f37
Reviewed-by: Jarek Kobus <jaroslaw.kobus@theqtcompany.com>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@theqtcompany.com>

src/plugins/git/gitclient.cpp

@@ -45,6 +45,7 @@
 
 #include <coreplugin/editormanager/editormanager.h>
 #include <coreplugin/icore.h>
+#include <coreplugin/idocument.h>
 #include <coreplugin/vcsmanager.h>
 #include <coreplugin/id.h>
 #include <coreplugin/iversioncontrol.h>
@@ -535,8 +536,6 @@ private:
     QRegExp m_progressExp;
 };
 
-
-
 IEditor *locateEditor(const char *property, const QString &entry)
 {
     foreach (IDocument *document, DocumentModel::openedDocuments())