Also accept timeout parameter in FakeMemCache

When fake.cache is set, current master keystoneclient
is setting timeout= parameter instead of time= parameter
in set due to https://bugs.launchpad.net/swift/+bug/1095730

Change-Id: Ied8ffd6ac9738951d48e74a496a8777928fcc0d9
Merge "Also accept timeout parameter in FakeMemCache"