Remove the const qualifier for the name field of AVFilterInOut, since

it is meant to be freed.
Fix warnings.

Originally committed as revision 19072 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavfilter/graphparser.h

@@ -29,7 +29,7 @@
  * A linked-list of the inputs/outputs of the filter chain.
  */
 typedef struct AVFilterInOut {
-    const char *name;
+    char *name;
     AVFilterContext *filter;
     int pad_idx;