Closes-Bug: #1522926 - Rectified contrail-dns.conf location

Discovery DNS was down as contrail-dns.conf was placed in /etc/contrail/dns instead of /etc/contrail

TESTING:
=========
1. provisioned 1 all-in-one node, verified that provision is completed
2. added image, created a network, subnetwork and 2 VMs, verified VMs are
active.
3. Logged-in to contrail-web ui and browsed to verify web-ui is up and
Running.
4. VMs are able to ping each other.
5. VM is able get http://169.254.269.254/openstack (metadata service)
6. Checked location of contrail-dns.conf.

Change-Id: I0d49926ff4a512b2ec4ee966c6c4d28f5941ed2b

contrail/environment/modules/contrail/lib/puppet/provider/contrail_dns_config/ini_setting.rb

@@ -22,7 +22,7 @@ def separator
   end
 
   def self.file_path
-    '/etc/contrail/dns/contrail-dns.conf'
+    '/etc/contrail/contrail-dns.conf'
   end
 
   # added for backwards compatibility with older versions

contrail/environment/modules/contrail/lib/puppet/type/contrail_dns_config.rb

@@ -3,7 +3,7 @@
   ensurable
 
   newparam(:name, :namevar => true) do
-    desc 'Section/setting name to manage from /etc/contrail/dns/control-dns.conf'
+    desc 'Section/setting name to manage from /etc/contrail/contrail-dns.conf'
     newvalues(/\S+\/\S+/)
   end