Move service_enable="YES" rc.conf(5) additions to

VM_RC_LIST and deduplicate.

Evaluate if firstboot_freebsd_update should be enabled
based on UNAME_r, because it is not supported for the
-CURRENT or -STABLE branches.

MFC after:	2 weeks
X-MFC-with:	r277458, r277536, r277606, r277609,
		r277836
Sponsored by:	The FreeBSD Foundation

release/tools/gce.conf

@@ -9,7 +9,8 @@ export VM_EXTRA_PACKAGES="firstboot-freebsd-update firstboot-pkgs \
 	google-startup-scripts"
 
 # Set to a list of third-party software to enable in rc.conf(5).
-export VM_RC_LIST="google_accounts_manager ntpd"
+export VM_RC_LIST="google_accounts_manager ntpd sshd firstboot_growfs \
+	firstboot_pkgs google_startup"
 
 vm_extra_install_base() {
 	echo 'search google.internal' > ${DESTDIR}/etc/resolv.conf
@@ -22,17 +23,16 @@ vm_extra_pre_umount() {
 dumpdev="AUTO"
 ifconfig_vtnet0="SYNCDHCP mtu 1460"
 ntpd_sync_on_start="YES"
-ntpd_enable="YES"
-sshd_enable="YES"
-google_accounts_manager_enable="YES"
-#disabled until I can figure out why the reboot for updates is hanging
-#firstboot_freebsd_update_enable="YES"
-#firstboot_pkgs_enable="YES"
+case \$(uname -r) in
+	*-BETA*|*-RC*|*-RELEASE*)
+		firstboot_freebsd_update_enable="YES"
+		;;
+	*)
+		;;
+esac
 # need to fill in something here
 #firstboot_pkgs_list=""
 panicmail_autosubmit="YES"
-firstboot_growfs_enable="YES"
-google_startup_enable="YES"
 EOF
 
 	cat << EOF >> ${DESTDIR}/boot/loader.conf