dash: Don't require the Representation @id. Many stream won't provide it.

Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>
(cherry picked from commit 4abd4469)
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

modules/stream_filter/dash/mpd/BasicCMParser.cpp

@@ -178,12 +178,9 @@ void    BasicCMParser::setRepresentations   (Node *root, Group *group)
 
         it = attributes.find( "id" );
         if ( it == attributes.end() )
-        {
             std::cerr << "Missing mandatory attribute for Representation: @id" << std::endl;
-            delete rep;
-            continue ;
-        }
-        rep->setId( it->second );
+        else
+            rep->setId( it->second );
 
         it = attributes.find( "bandwidth" );
         if ( it == attributes.end() )