Update requirements to 661e6

The requirements are updated to requirements project commit
661e6bad9e56dddd65a200dc08aedc00b9656312

 $ cd /opt/stack/requirements
 $ python update.py ../keystone

bp s3-token-to-keystoneclient

Closes-Bug: #1270909
Closes-Bug: #1277583
Related-Bug: #1178741
Change-Id: If7ddef69076e1b03c5efbf4f05bb349bbecfa015
Merge "Update requirements to 661e6"