fleetctl: raise default request timeout to 3s
fleetctl: raise default request timeout to 3s

Fix #743

webwlsong/fleet,hhoover/fleet,mookjp/fleet,coreos/fleet,jonboulle/fleet,esatterwhite/fleet,mwitkow/fleet,wuqixuan/fleet,hhoover/fleet,improbable-io/fleet,mookjp/fleet,dongsupark/fleet,jonboulle/fleet,octoblu/fleet,mwitkow-io/fleet,giantswarm/fleet,wuqixuan/fleet,bviswana101/fleet,mwitkow-io/fleet,mwhooker/fleet,thepwagner/fleet,mischief/fleet,paveltiunov/fleet,paveltiunov/fleet,bviswana101/fleet,endocode/fleet,dongsupark/fleet,bcwaldon/fleet,ecnahc515/fleet,ecnahc515/fleet,endocode/fleet,endocode/fleet,improbable-io/fleet,ecnahc515/fleet,WPMedia/fleet,mwitkow/fleet,mwhooker/fleet,jonboulle/fleet,dalbani/fleet,dalbani/fleet,bcwaldon/fleet,dongsupark/fleet,flandr/fleet,coreos/fleet,giantswarm/fleet,flandr/fleet,improbable-io/fleet,dalbani/fleet,webwlsong/fleet,WPMedia/fleet,bcwaldon/fleet,octoblu/fleet,mischief/fleet,coreos/fleet,thepwagner/fleet,esatterwhite/fleet,giantswarm/fleet