MAP: Return OBEX_HTTP_NOT_IMPLEMENTED response code for msgUpdate

In MAP profile message update is not implemented for sms/mms, but
we are returning OBEX_HTTP_OK response code for message update put
request, which is causing PTS test case to fail. Hence returning
proper response code to pass pts.

Change-Id: I40a45cea2d85750583bb7ae205d1ff57fe806a4d