FakeLoopingCall raises IOError
FakeLoopingCall raises IOError

All unittests using FakeLoopingCall raise an IOError if an initial
delay is not specified, because the default initial_dealy is -1.
Changing the default initial delay to 0.

story: 2005112
task: 29748
Change-Id: I6cbae0996c2347e25d8be617e4b3fd93f4d9cc95

openstack/magnum,openstack/magnum,ArchiFleKs/magnum,ArchiFleKs/magnum