output: added two missing mpd_return_pair() calls
output: added two missing mpd_return_pair() calls

1.) the first pair ("outputid") was never returned.

2.) when there is no output name, the last pair was never returned.

This patch also adds an assertion on pair==NULL in the error path.
An error should only be set when mpd_recv_pair() has returned NULL.

sl0th/libmpdclient,jagleeso/libmpdclient,yusiwen/libmpdclient,jagleeso/libmpdclient,jagleeso/libmpdclient,psych0tik/libmpdclient2,yusiwen/libmpdclient,sl0th/libmpdclient,yusiwen/libmpdclient,jwise/libmpdclient,jwise/libmpdclient,cmende/libmpdclient,cmende/libmpdclient,jwise/libmpdclient,psych0tik/libmpdclient2,sl0th/libmpdclient,cmende/libmpdclient,OpenInkpot-archive/iplinux-libmpdclient,OpenInkpot-archive/iplinux-libmpdclient