Do not print quality when stream copy,

Silence valgrind complaint:
==14746== Conditional jump or move depends on uninitialised value(s)
==14746==    at 0x43488DF: (within /lib/i686/cmov/libc-2.7.so)
==14746==    by 0x434ED81: __printf_fp (in /lib/i686/cmov/libc-2.7.so)
==14746==    by 0x434A3F3: vfprintf (in /lib/i686/cmov/libc-2.7.so)
==14746==    by 0x436EA93: vsnprintf (in /lib/i686/cmov/libc-2.7.so)
==14746==    by 0x4353234: snprintf (in /lib/i686/cmov/libc-2.7.so)
==14746==    by 0x806247C: print_report (ffmpeg.c:963)

Originally committed as revision 11728 to svn://svn.ffmpeg.org/ffmpeg/trunk