Documentation anomaly in TransportURL parse classmethod

The documentation for the classmethod `parse` states that

    The last parsed username and password will be propagated to the rest
    of hosts specified::
    user:pass@host1:port1,host2:port2
    [
    {"username": "user", "password": "pass", "host": "host1:port1"},
    {"username": "user", "password": "pass", "host": "host2:port2"}
    ]

However, in practice one needs to specify the usernames and passwords
individually with every host.

DocImpact: Documentation needs to be changed due anomaly in TransportURL
parse classmethod.

Change-Id: I1a9e07e0380a0d6f7d00731df93c9ba01ae20e0e
Closes-Bug: #1355684
Merge "Documentation anomaly in TransportURL parse classmethod"