Isolate change_server_password to use its own server

If this test is being run with others, it will mess up tests ahead
of it by changing the admin password of the instance.  Solving this
by creating a new server just for this test.

Change-Id: Id2c4fadd096db3d403a669139fe3caea98628c6b
Closes-Bug: #1632118
1 file changed