clean up USB ID override code and fix memory leak when no override was done
clean up USB ID override code and fix memory leak when no override was done


git-svn-id: 40dd595c6684d839db675001a64203a1457e7319@4112 67ed7778-7388-44ab-90cf-0a291f65f57c

gphoto/libgphoto2.OLDMIGRATION,gphoto/libgphoto2.OLDMIGRATION,gphoto/libgphoto2.OLDMIGRATION,gphoto/libgphoto2.OLDMIGRATION