response: fix command list assertion in mpd_response_finish()
response: fix command list assertion in mpd_response_finish()

When a list_OK was received, the assertion after mpd_recv_pair()
failed.  This patch corrects mpd_response_finish(), and makes it skip
all further responses properly.

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