Add dependency for openstackcleint

Add dependency for openstackcleint

Currently, the ci test result is error after the functest team modified
the parser dockerfile.
========= 1/4. Preparing VM image for parser... =========
Download image cirros-0.3.5-x86_64-disk.img...
./functest_run.sh: line 72: openstack: command not found
Registe image cirros-0.3.2-x86_64-uec...
./functest_run.sh: line 79: openstack: command not found
Clean-up the environment...
./functest_run.sh: line 243: openstack: command not found
Delete local image file cirros-0.3.2-x86_64-uec.img after test.
Delete local URL image file cirros-0.3.5-x86_64-disk.img after test.
./functest_run.sh: line 275: openstack: command not found
Delete user parser's role from project parser
./functest_run.sh: line 283: openstack: command not found
Delete user parser
./functest_run.sh: line 290: openstack: command not found
Delete project parser
./functest_run.sh: line 295: openstack: command not found
======================={ Parser functest end }==========================

it need to add python-openstackclient requirement in parser project.

JIRA: PARSER-166

Change-Id: I8b38325c602b508823d36709a93b1dd8739156f9
Signed-off-by: shangxdy <shang.xiaodong@zte.com.cn>