Fix the logic to access the location of a string to free when setting a new value for a string with av_set_string2(). Fix a segmentation fault. M    opt.c
Fix the logic to access the location of a string to free when
setting a new value for a string with av_set_string2().
Fix a segmentation fault.
M    opt.c


git-svn-id: a4d7c1866f8397a4106e0b57fc4fbf792bbdaaaf@14219 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b

prajnashi/ffmpeg,prajnashi/ffmpeg,prajnashi/ffmpeg,prajnashi/ffmpeg