GTK+ EWS needs to run update-webkitgtk-libs after applying a patch

GTK+ EWS needs to run update-webkitgtk-libs after applying a patch
https://bugs.webkit.org/show_bug.cgi?id=75857

Patch by Gustavo Noronha Silva <gustavo.noronha@collabora.com> on 2012-01-16
Reviewed by Adam Barth.

* Scripts/webkitdirs.pm:
(buildAutotoolsProject): move cleaning the build to happen early,
and handle --update-gtk right after that
* Scripts/webkitpy/common/config/ports.py:
(GtkPort.build_webkit_command): pass --update-gtk as an option to
build-webkit, so that it is used in the EWS

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@105142 268f45cc-cd09-0410-ab3c-d52691b4dbfc