linux: remove --disable-xshm flag
linux: remove --disable-xshm flag

This was added for testing.  We no longer need it.

BUG=46602

Review URL: http://codereview.chromium.org/6368062

git-svn-id: dd90618784b6a4b323ea0c23a071cb1c9e6f2ac7@73563 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser