Fix -no-gui

Fix -no-gui

-no-gui still tried to build the graphicssystem and inputmethod
plugins, both of which require QtGui

Merge-request: 1215
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@nokia.com>
(cherry picked from commit f0ae4f8ebdc6b7c50c163cfa29e686f3f87c8ba5)

Conflicts:
	src/plugins/plugins.pro

Change-Id: I74ced5817989604f3beebf1fcc60eabaf1fd8115
Reviewed-on: http://codereview.qt-project.org/4568
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@nokia.com>