[dconf] configure: depend on a released Vala

[Ryan Lortie <desrt src gnome org>]

commit c418dfff312738a883ef4907eaf2e1005a192b06
Author: Ryan Lortie <desrt desrt ca>
Date:   Wed Mar 12 09:29:44 2014 -0400

    configure: depend on a released Vala
    
    dconf is tested as working with Vala 0.18.

 configure.ac |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 4624e73..f30ffb4 100644
--- a/configure.ac
+++ b/configure.ac
@@ -20,7 +20,7 @@ fi
 AC_PROG_CC
 AC_CHECK_LIB(c, dlsym, LIBDL="", [AC_CHECK_LIB(dl, dlsym, LIBDL="-ldl")])
 AC_SUBST(LIBDL)
-AM_PROG_VALAC([0.17.0])
+AM_PROG_VALAC([0.18.0])
 AC_PROG_RANLIB
 AC_ARG_ENABLE(man,
               [AS_HELP_STRING([--enable-man],