update trixtel regex to work better

git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@2195 d0543943-73ff-0310-b7d9-9358b9ac24b2

conf/freeswitch.xml

@@ -356,7 +356,7 @@
     <!-- *NOTE* The special context name 'any' will match any context -->
     <context name="default">
       <extension name="tollfree">
-        <condition field="destination_number" expression="^(18[0{2}8{2}7{2}6{2}]\d{7})">
+        <condition field="destination_number" expression="^(18(0{2}|8{2}|7{2}|6{2})\d{7})$">
           <action application="bridge" data="exosip/$1-freeswitch@voip.trxtel.com"/>
         </condition>
       </extension>