Undefine the macro which defines fprintf as please_use_av_log so that

fprintf can be used for printing to file.
Patch by JonY <10walls __AT__ gmail @@dot@@ com>

Originally committed as revision 15220 to svn://svn.ffmpeg.org/ffmpeg/trunk

vhook/fish.c

@@ -48,6 +48,7 @@
 #include "libavformat/framehook.h"
 #include "libavcodec/dsputil.h"
 #include "libswscale/swscale.h"
+#undef fprintf
 
 static int sws_flags = SWS_BICUBIC;
 

vhook/ppm.c

@@ -29,6 +29,7 @@
 #include "libavformat/framehook.h"
 #include "libavformat/avformat.h"
 #include "libswscale/swscale.h"
+#undef fprintf
 
 static int sws_flags = SWS_BICUBIC;