archlinux: add correct section to qubes-noupgrade.conf

Some libalpm based tools fail to correctly parse config files without
sections.

archlinux/PKGBUILD-qubes-noupgrade.conf

@@ -1,2 +1,3 @@
+[options]
 NoUpgrade = etc/pam.d/su
-NoUpgrade = etc/pam.d/su-l
+NoUpgrade = etc/pam.d/su-l