cogl_path_new now takes a CoglContext pointer which it keeps a pointer
to instead of relying on the global context.
Reviewed-by: Robert Bragg <robert@linux.intel.com>
(cherry picked from commit afc63f8211c230f8fd1f7801f9085627c46a8661)
Since we can't change the api on this branch this just applies
the internal cleanups so we depend less on _COGL_GET_CONTEXT