Fix reconciler test to calc lastmodified as UTC
Fix reconciler test to calc lastmodified as UTC

Swift reconciler calculates the last-modified date as UTC but
current test calculates it as local time zone. It triggers unit
test failure in non-UTC environment.

This patch fixes the test to calculate the last-modified as UTC
as well.

Change-Id: Ia0053f350daf2cb8c61ac01a933924b6e4b0cb37
Closes-Bug: #1526588

notmyname/swift,swiftstack/swift,redbo/swift,tipabu/swift,williamthegrey/swift,openstack/swift,prashanthpai/swift,matthewoliver/swift,nadeemsyed/swift,revoer/keystone-8.0.0,levythu/swift,openstack/swift,tipabu/swift,psachin/swift,redbo/swift,levythu/swift,notmyname/swift,hurricanerix/swift,nadeemsyed/swift,clayg/swift,matthewoliver/swift,psachin/swift,rackerlabs/swift,hurricanerix/swift,smerritt/swift,smerritt/swift,nadeemsyed/swift,swiftstack/swift,larsbutler/swift,nadeemsyed/swift,psachin/swift,hurricanerix/swift,tipabu/swift,clayg/swift,matthewoliver/swift,swiftstack/swift,revoer/keystone-8.0.0,openstack/swift,matthewoliver/swift,rackerlabs/swift,tipabu/swift,aerwin3/swift,notmyname/swift,hurricanerix/swift,openstack/swift,aerwin3/swift,clayg/swift,prashanthpai/swift,larsbutler/swift,psachin/swift,williamthegrey/swift,notmyname/swift,clayg/swift,smerritt/swift,smerritt/swift