Removes unnecessary utf-8 encoding

This patches removes unnecessary utf-8 encoding in
tempest/api/orchestration/stacks/test_swift_resources.py
tempest/tests/lib/test_tempest_lib.py
doc/source/conf.py
releasenotes/source/conf.py

For tempest/api/baremetal/admin/test_chassis.py
==> Still need the encoding for Non-ASCII characters in the file

Change-Id: I2e1bff1f64dfe08f40562fa51e08a8ba25c9c3ae
4 files changed