Updates (probably) outdated comments in libvlc_InternalCreate (the commented behavior seems to have been moved to the calling function) in lib/core.c

Signed-off-by: Felix Paul Kühne <fkuehne@videolan.org>
src/playlist/thread.c: Use the macro to lock/unlock the playlist as in the rest of the file

Signed-off-by: Felix Paul Kühne <fkuehne@videolan.org>