MT#59470 fix REGISTER template

Message was not properly built. Everything after Contact was not
included due to an empty line when ua is empty

Change-Id: I1e0851149103851bfd9228d1cf840b02144230d7

scenarios/templates/sipp_scenario_responder_reg.xml.tt2

@@ -12,10 +12,10 @@
       Call-ID: NGCP%[field4 file="callee.csv" line=0]%///[call_id]
       CSeq: 1 REGISTER
       Contact: sip:[field0 file="callee.csv" line=[% line -%]]@[local_ip]:[local_port];transport=[transport][% IF q %];q=[% q %][% END %]
-      [% IF ua %]User-Agent: [% ua %][% END %]
       Expires: 600
       Max-Forwards: 70
       Content-Length: 0
+      [% IF ua %]User-Agent: [% ua %][% END %]
 
     ]]>
   </send>
@@ -37,10 +37,10 @@
       CSeq: 2 REGISTER
       [field2 file="callee.csv" line=[% line -%]]
       Contact: sip:[field0 file="callee.csv" line=[% line -%]]@[local_ip]:[local_port];transport=[transport][% IF q %];q=[% q %][% END %]
-      [% IF ua %]User-Agent: [% ua %][% END %]
       Expires: 600
       Max-Forwards: 70
       Content-Length: 0
+      [% IF ua %]User-Agent: [% ua %][% END %]
 
     ]]>
   </send>