fix warning reported by Intel C compiler:
libavcodec/h264_parser.c(77): warning #589: transfer of control
bypasses initialization of:
           variable "v" (declared at line 58)
                 goto found;
This new form also improves readability.

Patch by Diego 'Flameeyes' Pettenò %flameeyes A gmail P com%

Originally committed as revision 15526 to svn://svn.ffmpeg.org/ffmpeg/trunk
