Make ffserver -h exit 0.

patch by Stefano Sabatini, stefano.sabatini-lala poste it

Originally committed as revision 10103 to svn://svn.ffmpeg.org/ffmpeg/trunk

ffserver.c

@@ -4443,7 +4443,7 @@ int main(int argc, char **argv)
         case '?':
         case 'h':
             show_help();
-            exit(1);
+            exit(0);
         case 'n':
             no_launch = 1;
             break;