search - remove commented check_lucene_frontend

already commented out, see faidon's comment why

not used, and checkcommand suggested for deletion
in I5a0d363a93a614b5

just ran across it by accident because of I53f0ab311597f4b78b7

Change-Id: If6c1daa28f8e3b331ee98f5de869d28ee767009e