Remove python-swiftclient from test-requirements.txt

It seems that it was added back in Liberty where an effort was
started to setup functional tests, however it is not used at the
moment.

This patch removes it from the list of dependencies.  With time,
Tempest should handle all integration checks.

Change-Id: I9e1990e93abc6e3001f499ccc8d40b6104ed2d93

test-requirements.txt

@@ -21,7 +21,6 @@ python-ceilometerclient>=2.5.0 # Apache-2.0
 python-heatclient>=1.6.1 # Apache-2.0
 python-neutronclient>=5.1.0 # Apache-2.0
 python-openstackclient>=3.3.0 # Apache-2.0
-python-swiftclient>=3.2.0 # Apache-2.0
 pytz>=2013.6 # MIT
 sphinx>=1.5.1 # BSD
 testrepository>=0.0.18 # Apache-2.0/BSD