Rename gyp variable use_titlecase_in_grd_files -> use_titlecase_in_grd.

The name changes in https://codereview.chromium.org/552203002/

Patch by Jacek Oleksy <joleksy@opera.com>.

Review URL: https://breakpad.appspot.com/5694002/


git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1371 4c0a9323-5329-0410-9bdc-e9ce6186880e