Fix hiredis install to only run if it was found, not just if we set HIREDIS_ROOT.
Fix hiredis install to only run if it was found, not just if we set HIREDIS_ROOT.

sirikata/sirikata,sirikata/sirikata,sirikata/sirikata,sirikata/sirikata,sirikata/sirikata,sirikata/sirikata,sirikata/sirikata,sirikata/sirikata