afs: Fix error handling of the select command.

afs: Fix error handling of the select command.

com_select() returns success even if the mood or playlist could not
be activated. This commit changes the function to return the error
code from activate_mood_or_playlist() instead.

The function had another minor issue: If the current mood is the
dummy mood, and we failed to switch to the given mood or playlist,
and also failed to switch back to the dummy mood, we try a second
time to activate the dummy mood. This should not happen, but let's
fix it anyway.