[tracker] build: Require Vala >= 0.18.0

[Jürg Billeter <juergbi src gnome org>]

commit 40b0cbebec519429c137883fb49ca8f3a4c32d5b
Author: Jürg Billeter <j bitron ch>
Date:   Thu Jan 23 08:47:38 2014 +0100

    build: Require Vala >= 0.18.0
    
    Vala 0.16 has a bug in the g_dbus_message_get_body binding.

 autogen.sh |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/autogen.sh b/autogen.sh
index 6d7ad1c..8e016e9 100755
--- a/autogen.sh
+++ b/autogen.sh
@@ -3,7 +3,7 @@
 #
 # NOTE: compare_versions() is stolen from gnome-autogen.sh
 
-REQUIRED_VALA_VERSION=0.16.0
+REQUIRED_VALA_VERSION=0.18.0
 
 # Usage:
 #     compare_versions MIN_VERSION ACTUAL_VERSION