song: added range check to mpd_song_clear_tag()
song: added range check to mpd_song_clear_tag()

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