[EFL] --minimal build fails because of incorrect usage of GENERATE_THEME in CMakeLists.txt
https://bugs.webkit.org/show_bug.cgi?id=113902

Unreviewed.

Patch by Ed Bartosh <bartosh@gmail.com> on 2013-04-07

* platform/efl/DefaultTheme/CMakeLists.txt:
Put possibly empty variable after non-empty to avoid space
at the beginning of string parameter

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@147886 268f45cc-cd09-0410-ab3c-d52691b4dbfc