Silent some warnings under clangs
Silent some warnings under clangs

cern-it-sdc-id/davix,cern-it-sdc-id/davix,cern-it-sdc-id/davix,EricKTCheung/davix,cern-it-sdc-id/davix,EricKTCheung/davix,EricKTCheung/davix,EricKTCheung/davix