When a user is created without a password then no parameter called
'password' should be submitted to the keystone API. This removes the
incorrect 'password' with null being supplied.
Closes-Bug: 2136148
Change-Id: If1c2eb5db360764a5f7660ce4e5353da85b6d3da
Signed-off-by: Doug Goldstein <cardoe@cardoe.com>