StatusHistorySuite.TestPruneStatusHistory

As seen in
    http://reports.vapour.ws/releases/issue/566ecf44749a5663477fdce3

Seveal tests related to history fail on windows with go 1.6

Many status tests fail on windows like this:
status_util_test.go:33:
    c.Check(statusInfo.Data, jc.DeepEquals, map[string]interface{}{"$foo": expect})
... obtained map[string]interface {} = map[string]interface {}{"$foo":5}
... expected map[string]interface {} = map[string]interface {}{"$foo":8}
... mismatch at ["$foo"]: unequal; obtained 5; expected 8

The affected tests are
    StatusHistorySuite.TestPruneStatusHistory
    UnitStatusSuite.TestStatusHistoryLong
    UnitStatusSuite.TestStatusHistoryShort
    StatusUnitAgentSuite.TestStatusHistoryLong
    StatusUnitAgentSuite.TestStatusHistoryShort