Remove obsolete warning about concurrent executions

 Remove warning about unparameterized --display as it is
 now parameterized (this commit is a follow-up to comments
 in already merged https://gerrit.onap.org/r/#/c/87357/)

 Added also brackets for namespace parameter in usage guide

Change-Id: I78a753b026e3e9b410798687b28ad0ca1115703e
Issue-ID: OOM-1844
Signed-off-by: kaihlavi <l.kaihlavirt@partner.samsung.com>
2 files changed