`use-readdirp` has an optional argument in argp - specifying just `--use-readdirp` command line should not 'turn off' readdirp, since that undermines the meaning of such an argument. Change-Id: I965d87e29bd0d61997d9be96fa698e270a2ee173 BUG: 983477 Signed-off-by: Harshavardhana <harsha@harshavardhana.net> Reviewed-on: http://review.gluster.org/5851 Tested-by: Gluster Build System <jenkins@build.gluster.com> Reviewed-by: Anand Avati <avati@redhat.com>