Fix misspellings in python openstacksdk

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

Change-Id: Icba80ebaf3f7e9dbe48ed45a9eee30a09270135e
Closes-Bug: #1257295
Merge "Fix misspellings in python openstacksdk"