[GTK] acceleration_backend_description does not concatenate "(gles2"
https://bugs.webkit.org/show_bug.cgi?id=112405

Patch by Jae Hyun Park <jae.park@company100.net> on 2013-03-15
Reviewed by Martin Robinson.

In FindDependencies.m4, acceleration_backend_description string does not
concatenate if there is a space between the operator and the operand.

* Source/autotools/FindDependencies.m4:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@145912 268f45cc-cd09-0410-ab3c-d52691b4dbfc