OCI: Remove dead code

We don't need to pick a repository URL when all we're doing is enabling
one which was specified in /etc/pkg/.

Reviewed by:	dch, imp
Fixes:	c73ae67348 ("release/tools: use same pkg settings ...")
MFC after:	1 week
Differential Revision:	https://reviews.freebsd.org/D60868

(cherry picked from commit 93c05b743e)

release/tools/oci-image-static.conf

@@ -27,14 +27,6 @@ oci_image_build() {
 	    UNTRUSTPATH=${srcdir}/secure/caroot/untrusted \
 	    certctl -c rehash
 	# Generate a suitable repo config for pkgbase
-	case ${branch} in
-		CURRENT|STABLE|BETA*)
-			repo=base_latest
-			;;
-		*)
-			repo=base_release_${minor}
-			;;
-	esac
 	mkdir -p $m/usr/local/etc/pkg/repos
 	cat > $m/usr/local/etc/pkg/repos/FreeBSD.conf <<EOF
 FreeBSD-base: {