community/libcanberra: remove oss backend

Open Sound System (OSS) is the ancestor of ALSA. Alpine doesn't provide
OSS packages, so this backend is useless here.

community/libcanberra/APKBUILD

@@ -47,7 +47,8 @@ build() {
 		--prefix=/usr \
 		--sysconfdir=/etc \
 		--mandir=/usr/share/man \
-		--infodir=/usr/share/info
+		--infodir=/usr/share/info \
+		--disable-oss
 	make
 }