Updated openstack/openstack
Project: openstack/ceilometer  2ea0639e933cac12497743b1aea4bd224c5fa3d0

replaced unicode() with six.text_type()

According to https://wiki.openstack.org/wiki/Python3 unicode()
should be replaced with six.text_type().

Change-Id: If314b7ada4976a4cf05f16c2bb2beb54d1f595a1