release: Spell metalog_add_data conventionally

Reviewed by:	markj
MFC after:	3 days
Fixes: f1995d6fc1 ("release: Prepare GCE cloudware images for building as non-root")
Differential Revision:	https://reviews.freebsd.org/D53530

release/tools/gce.conf

@@ -21,7 +21,7 @@ vm_extra_install_base() {
 	echo 'search google.internal' > ${DESTDIR}/etc/resolv.conf
 	echo 'nameserver 169.254.169.254' >> ${DESTDIR}/etc/resolv.conf
 	echo 'nameserver 8.8.8.8' >> ${DESTDIR}/etc/resolv.conf
-	metalog_add ./etc/resolv.conf
+	metalog_add_data ./etc/resolv.conf
 }
 
 vm_extra_pre_umount() {