TestDurationToKillTime is flaky

[asobti]

Fails occasionally because the result of the test is time-dependent: https://github.com/asobti/kube-monkey/blob/ebe3dbf56e1b30ffaeae51baa13528f302cf7147/chaos/chaos_test.go#L149-L152

--- FAIL: TestSuite (0.02s)
    --- FAIL: TestSuite/TestDurationToKillTime (0.00s)
    	chaos_test.go:151: 
    			Error Trace:	chaos_test.go:151
    			Error:      	Max difference between 2018-11-25 05:07:14.010708836 +0000 UTC m=+0.017815678 and 2018-11-25 05:07:14.011653307 +0000 UTC m=+0.018760214 allowed is 57.703µs, but difference was -944.536µs
    			Test:       	TestSuite/TestDurationToKillTime

[asobti]

Disabled test in #133 until it is fixed