Remove unittest from sources list of iOS client xcodeproj.

This unittest has a main(), which causes linker errors when the library is
linked into an application.

Patch by:blundell@chromium.org

R=qsr@chromium.org

Review URL: https://breakpad.appspot.com/640002

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1221 4c0a9323-5329-0410-9bdc-e9ce6186880e