means the affected tables can have private tables involved.
That implies QueryTablesApi will need the proper user to use
CDB_QueryTables. So we store it in a request context to use it in
the afterLayergroupCreate call.
Tiles for these layergroups will fail to add a X-Cache-Channel
header because it won't be possible to use the proper user within
those tiles. Ok, they will fail if they are not requested through
the same tiler instance because if they are they most likely will
reuse the in memory cache.
See https://github.com/CartoDB/Windshaft-cartodb/issues/253
c17af23a40