entity: free the first mpd_pair
entity: free the first mpd_pair

Fix a memory leak.

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