Correct print pattern in rest_client
Correct print pattern in rest_client

The statement:
    pattern = """Unexpected http success status code {0},
                 The expected status code is {1}"""

will print more spaces than expected, something like:
Details: Unexpected http success status code 200,
                         The expected status code is [204]

This is to fix it.

Change-Id: If4a299828dce4a835d5d178deff09e01950a8915

masayukig/tempest,Juniper/tempest,openstack/tempest,cisco-openstack/tempest,vedujoshi/tempest,masayukig/tempest,Juniper/tempest,vedujoshi/tempest,openstack/tempest,cisco-openstack/tempest