Git: Save settings

VCSBaseClient handles saving of settings for us, but we do not
use that yet, so we have to do that ourselves:-(

Change-Id: I731d01d429497581fad814effd68bbd784e05fe8
Reviewed-on: http://codereview.qt-project.org/6080
Reviewed-by: Tobias Hunger <tobias.hunger@nokia.com>

src/plugins/git/gitplugin.cpp

@@ -1070,6 +1070,7 @@ void GitPlugin::setSettings(const GitSettings &s)
         return;
 
     m_settings = s;
+    m_gitClient->saveSettings();
     static_cast<GitVersionControl *>(versionControl())->emitConfigurationChanged();
 }