use gotest.tools assertions in docker_cli_push_test.go
use gotest.tools assertions in docker_cli_push_test.go

Signed-off-by: Tibor Vass <3f1326dff4d85ad4ec938fb33f64575ace96db26@docker.com>

jameszhan/docker,pradipd/moby,tmp6154/docker,yongtang/docker,justincormack/docker,crosbymichael/docker,paralin/docker,docker/docker,Ramzec/docker,dims/docker,cpuguy83/docker,moul/docker,yosifkit/docker,trebonian/docker,gnailuy/docker,nawawi/docker,mahak/docker,AkihiroSuda/docker,paralin/docker,flavio/docker,ibuildthecloud/docker,cpuguy83/docker,konstruktoid/docker-upstream,jimjag/docker,konstruktoid/docker-upstream,SvenDowideit/docker,thaJeztah/docker,nawawi/docker,estesp/docker,jvanz/docker,flavio/docker,moul/docker,konstruktoid/docker-1,konstruktoid/docker-upstream,vdemeester/docker,AkihiroSuda/docker,tmp6154/docker,trebonian/docker,gnailuy/docker,yosifkit/docker,bearstech/moby,dims/docker,vdemeester/docker,moul/docker,yosifkit/docker,ibuildthecloud/docker,flavio/docker,jvanz/docker,konstruktoid/docker-1,gnailuy/docker,nawawi/docker,mahak/docker,moul/docker,konstruktoid/docker-upstream,Mokolea/docker,jameszhan/docker,cpuguy83/docker,docker/docker,konstruktoid/docker-1,ibuildthecloud/docker,SvenDowideit/docker,trebonian/docker,jthelin/docker,djs55/docker,Ramzec/docker,Mokolea/docker,pradipd/moby,unclejack/docker,jvanz/docker,Mokolea/docker,nawawi/docker,trebonian/docker,pradipd/moby,kolyshkin/moby,SvenDowideit/docker,bearstech/moby,jimjag/docker,jimjag/docker,ibuildthecloud/docker,jameszhan/docker,unclejack/docker,ibuildthecloud/docker,thaJeztah/docker,moby/moby,AkihiroSuda/docker,AkihiroSuda/docker,kojiromike/docker,mahak/docker,nalind/docker,yongtang/docker,Mokolea/docker,kolyshkin/moby,cpuguy83/docker,djs55/docker,thaJeztah/docker,nalind/docker,moby/moby,crosbymichael/docker,moby/moby,mahak/docker,kojiromike/docker,yongtang/docker,jthelin/docker,paralin/docker,djs55/docker,justincormack/docker,nalind/docker,kojiromike/docker,unclejack/docker,flavio/docker,jimjag/docker,paralin/docker,docker/docker,justincormack/docker,estesp/docker,tmp6154/docker,thaJeztah/docker,dims/docker,Ramzec/docker,estesp/docker,gnailuy/docker,Ramzec/docker,moby/moby,bearstech/moby,vdemeester/docker,nalind/docker,bearstech/moby,yosifkit/docker,crosbymichael/docker,kolyshkin/moby