Cleanup of docs for integration tests

Some parts of text from https://github.com/openstack/sahara/blob/master/sahara/tests/integration/README.rst
are displayed not correctly. This patch corrects that.

Change-Id: Iec7b6b51530d96739f640a3fdfe1e894a67ed4a9
(cherry picked from commit 1fa25cd90a4997cc01356dd51b3d2d9bd31e1fbd)