Fix a misspelled word and correct the description for parameter
'api_version'; the only valid value is '1' (because we only have v1).
Change-Id: I51e23f783de5000df96dca26cd87244c3733d359
Raise an exception if configured credentials are not sufficient
for obtaining an endpoint and token.
Change-Id: Ie11a25eb67da2d2c2c8ef40ab984eb2ecb77fdf9
Closes-Bug: 1290601