Update help text around container ACL syntax
Update help text around container ACL syntax

The patch add the information about the syntax of provding read and
write access to the users within a project.

The current status is:
account:* does not work with tempauth
account does not work with keystoneauth

Furthermore, the concept of "account" is fuzzy. It could be a
"project", but even that doesn't distinguish between a project
id and a project name.

Change-Id: I4462230fe05aa4a742e825f5b6312deb93bc1170
Closes-Bug: #1587677

sohonetlabs/python-swiftclient,sohonetlabs/python-swiftclient,openstack/python-swiftclient,openstack/python-swiftclient