1.6.1dev: fix empty <caption class="trac-group"> element from query view without group parameter

git-svn-id: http://trac.edgewall.org/intertrac/log:/branches/1.6-stable@17874 af82e41b-90c4-0310-8c96-b1721e28e2e2

Author: jomae

trac/ticket/templates/query_results.html

@@ -62,7 +62,7 @@ <h2 class="report-result" >
   # endmacro
 
   <table class="listing tickets">
-    # if len(groups) > 0:
+    # if len(groups) > 0 and groups[0][0] is not none:
     <caption class="trac-group">
       ${group_heading(*groups[0])}
     </caption>