HBASE-7353 [shell] have list and list_snapshot return jruby string arrays.

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/hbase-7290@1445789 13f79535-47bb-0310-9956-ffa450edef68

hbase-server/src/main/ruby/shell/commands/list.rb

@@ -40,6 +40,7 @@ EOF
         end
 
         formatter.footer(now, list.size)
+        return list
       end
     end
   end

hbase-server/src/main/ruby/shell/commands/list_snapshots.rb

@@ -45,6 +45,7 @@ EOF
         end
 
         formatter.footer(now, list.size)
+        return list.map { |s| s.getName() }
       end
     end
   end