build: add flags for go1.4 static build
build: add flags for go1.4 static build

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