Previously, when the --username flag was provided to RBTools and a

session cookie already existed, RBTools would prompt for the password

but never use it (because of the session cookie). We now clear the

session cookie when the --username flag is given.

Ran unit tests.
Attempted to post a review request with the --username parameter and

a bogus password; the review request was not created. It was created

when the correct password was used.