Docs for v3 credentials
Docs for v3 credentials

The v3 credentials API was unusable because the docs didn't
include any information about what parameters are passed to the
CredentialManager methods.

Also, the attributes for the Credential objects was incomplete.

Change-Id: I6872f217c75ae94611749c59be0dd6941170fd57

ging/python-keystoneclient,magic0704/python-keystoneclient,klmitch/python-keystoneclient,darren-wang/ksc,klmitch/python-keystoneclient,magic0704/python-keystoneclient,darren-wang/ksc,ging/python-keystoneclient,sdpp/python-keystoneclient,sdpp/python-keystoneclient,Mercador/python-keystoneclient,Mercador/python-keystoneclient