Changed an ASSERT to a LOG_ERROR for an error that could be handled gracefully, but
        whose assertion was reproducibly causing a build bot failure

        * Misc/WebIconDatabase.m:
        (-[WebIconDatabase _releaseIconForIconURLString:]):



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@15214 268f45cc-cd09-0410-ab3c-d52691b4dbfc