Updated openstack/openstack
Project: openstack/python-swiftclient  76c42a820cd3a0f08cfc7a3fa32ca012b457f47f

change assert_ to assertTrue

According to http://docs.python.org/2/library/unittest.html
assert_ is a deprecated alias of assertTrue.

Change-Id: I18db0af72934dde4498502fb29579941d020cf01