configure.ac: use dots when printing dbus version
Bump mate-desktop required to version 1.9.4

The materr* changes are not in mate-desktop 1.9.3 yet.
Add back Glib 2.32 support
Drop back to Glib 2.32 in configure.ac
Revert "Drop back to Glib 2.32 in configure.ac"

This reverts commit d1381afe0285c1fb4dabb2ccf3ad496efab9f3ff.
Revert "Add back Glib 2.32 support"

This reverts commit ddc4152abebd61f14055dec8c2f7c4c1e0d2ddd0.