fix variable in templates

puppet variables aren't variables in templates. Therefore
has_variable? is not working as expected.

manifests/vpn/conf.pp

@@ -1,7 +1,7 @@
 # $name => Name of network=ring
 define tinc::vpn::conf (
   $ensure = present,
-  $connectTo = '',
+  $connectTo = 'absent',
 ){
 
  file { "/etc/tinc/${name}/tinc.conf":

templates/tinc.conf.erb

@@ -5,8 +5,8 @@ Device = /dev/net/tun
 Mode = switch
 #Mode = router
 
-<% if has_variable?(connectTo) -%>
-ConnectTo = <%= connectTo %>
+<% unless connect_to.to_s == 'absent' -%>
+ConnectTo = <%= connect_to %>
 <% end -%>
 
 #GraphDumpFile = /tmp/tincdump