agent: fix test failures by sorting slices before comparison
agent: fix test failures by sorting slices before comparison

when GOMAXPROCS is >, goroutine scheduling affects the order in which
slice elements get appended in the tests. use sort.Strings before
calling reflect.DeepEqual so that the ordering of the elements is
consistent.

wuqixuan/fleet,mookjp/fleet,coreos/fleet,paveltiunov/fleet,giantswarm/fleet,octoblu/fleet,paveltiunov/fleet,coreos/fleet,giantswarm/fleet,WPMedia/fleet,improbable-io/fleet,webwlsong/fleet,octoblu/fleet,endocode/fleet,dongsupark/fleet,dongsupark/fleet,thepwagner/fleet,endocode/fleet,endocode/fleet,thepwagner/fleet,improbable-io/fleet,flandr/fleet,mwhooker/fleet,jonboulle/fleet,esatterwhite/fleet,bviswana101/fleet,dalbani/fleet,webwlsong/fleet,dalbani/fleet,WPMedia/fleet,dalbani/fleet,improbable-io/fleet,wuqixuan/fleet,flandr/fleet,jonboulle/fleet,esatterwhite/fleet,giantswarm/fleet,jonboulle/fleet,mookjp/fleet,coreos/fleet,dongsupark/fleet,bviswana101/fleet,mwhooker/fleet