[mythtv] Crash in mythmusic

[Joseph A. Caputo]

Just noticed this, running CVS as of 11/04 (time to update, I guess).  
Mythfrontend crashes when ripping a CD in mythmusic if the destination 
directory isn't writeable.  Looks like the Encoder class (and 
descendants) don't handle the case where the file can't be opened for 
writing, which should result in a NULL value for FILE * out (other than 
printing an error message).  Don't know if it's only the Vorbis encoder 
that has a problem with this, as the file pointer is simply passed in 
to the libvorbis/libmad/libflac routines.  Probably should be aborting 
the rip gracefully instead.

If I have time I'll look into a fix, but I just wanted to 'put it out 
there' in case anyone else wants to take a crack at it.  I realize the 
whole CD ripping thing is slated for an overhaul soon, what with all of 
the mfd and MediaHandler stuff going in, but I figured I'd mention this 
anyway.

-JAC