Port _validate_time() to Python 3
Port _validate_time() to Python 3

The change Ib342ef6640efbc3d76c4bafc622ccfdfa3d16ade added a new
_validate_time() function for API v1. On Python 2, the function
relies on the datetime module to get a ValueError for datetime with
year older than 1900. On Python 3, the datetime module accepts years
before 1900 and so we have to test manually.

Change-Id: Id1dbf98ecf23e401f696a575dfea80fac2e297ed

stevelle/glance,dims/glance,klmitch/glance,openstack/glance,stevelle/glance,dims/glance,klmitch/glance,openstack/glance,rajalokan/glance,rajalokan/glance,openstack/glance