adapt tar_options handling

The original tar_options=$tar_options statement was noop. Align the
behavior to match other options handling.

cqfd

@@ -264,10 +264,9 @@ make_archive() {
 		tar_opts='--transform s/.*\///g'
 	fi
 
-	# setting tar_options will add the following options to the tar
-	# command
-	if [ -n "$tar_options" ]; then
-		tar_opts="$tar_opts $tar_options"
+	# setting tar_options=x will pass the options to tar
+	if [ "$release_tar_opts" ]; then
+		tar_opts+=" $release_tar_opts"
 	fi
 
 	# support the following archive formats
@@ -385,7 +384,7 @@ config_load() {
 	release_files="$files"
 	release_archive="$archive"
 	release_transform="$tar_transform"
-	tar_options="$tar_options"
+	release_tar_opts="$tar_options"
 
 	dockerfile="${cqfddir}/${distro:-docker}/Dockerfile"