Fix misspellings in openstack-nose

Fix misspellings detected by:
* pip install misspellings
* git ls-files | grep -v locale | misspellings -f -

Change-Id: I2770087b9cec76665ae9d2e2e2f4f4334b7adf0d
Closes-Bug: #1257295
Merge "Fix misspellings in openstack-nose"