Make rle_code int everywhere instead of signed char.

Fixes playback of auth_generator-demo.mov, for rle_code == -128 the assignement
rle_code = -rle_code would overflow.
Patch by matthieu castet (castet matthieu (at) free fr)

Originally committed as revision 4669 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/qtrle.c

@@ -251,7 +251,7 @@ static void qtrle_decode_16bpp(QtrleContext *s)
     int header;
     int start_line;
     int lines_to_change;
-    signed char rle_code;
+    int rle_code;
     int row_ptr, pixel_ptr;
     int row_inc = s->frame.linesize[0];
     unsigned short rgb16;
@@ -329,7 +329,7 @@ static void qtrle_decode_24bpp(QtrleContext *s)
     int header;
     int start_line;
     int lines_to_change;
-    signed char rle_code;
+    int rle_code;
     int row_ptr, pixel_ptr;
     int row_inc = s->frame.linesize[0];
     unsigned char r, g, b;
@@ -408,7 +408,7 @@ static void qtrle_decode_32bpp(QtrleContext *s)
     int header;
     int start_line;
     int lines_to_change;
-    signed char rle_code;
+    int rle_code;
     int row_ptr, pixel_ptr;
     int row_inc = s->frame.linesize[0];
     unsigned char r, g, b;