Static checking by GCC 4.8-20130319.

Static checking by GCC 4.8-20130319.

* image.c (gif_load): Assume pass < 3 to pacify GCC.
* process.c (Fset_process_datagram_address)
(Fmake_network_process): Check get_lisp_to_sockaddr_size return value.
* xdisp.c (get_char_face_and_encoding):
(get_glyph_face_and_encoding): Ensure that *CHAR2B is initialized.
(get_glyph_face_and_encoding): Prepare face before possibly using it.
(get_per_char_metric): Don't use CHAR2B if it might not be initialized.