set the kv-provider driver labels only if it is a valid config
set the kv-provider driver labels only if it is a valid config

without this fix, overlay driver returns an error and that causes the
daemon to quit.

Signed-off-by: Madhu Venugopal <d22477479bbf55ba62bd822f4112c80f292c7805@docker.com>

moby/moby,moby/moby,cpuguy83/docker,nawawi/docker,Mokolea/docker,trebonian/docker,konstruktoid/docker-upstream,gnailuy/docker,jimjag/docker,gnailuy/docker,moby/moby,Ramzec/docker,mahak/docker,konstruktoid/docker-upstream,nalind/docker,moul/docker,yosifkit/docker,docker/docker,Mokolea/docker,mahak/docker,nawawi/docker,thaJeztah/docker,bearstech/moby,trebonian/docker,yosifkit/docker,nawawi/docker,vdemeester/docker,gnailuy/docker,bearstech/moby,djs55/docker,trebonian/docker,moul/docker,djs55/docker,nalind/docker,cpuguy83/docker,bearstech/moby,flavio/docker,AkihiroSuda/docker,docker/docker,konstruktoid/docker-upstream,trebonian/docker,thaJeztah/docker,jimjag/docker,AkihiroSuda/docker,vdemeester/docker,paralin/docker,thaJeztah/docker,mahak/docker,AkihiroSuda/docker,mahak/docker,jameszhan/docker,paralin/docker,yosifkit/docker,Mokolea/docker,jthelin/docker,moby/moby,jimjag/docker,Ramzec/docker,Ramzec/docker,bearstech/moby,paralin/docker,gnailuy/docker,jameszhan/docker,moul/docker,Ramzec/docker,cpuguy83/docker,jameszhan/docker,AkihiroSuda/docker,yosifkit/docker,flavio/docker,moul/docker,flavio/docker,thaJeztah/docker,jimjag/docker,Mokolea/docker,nalind/docker,jthelin/docker,paralin/docker,vdemeester/docker,djs55/docker,flavio/docker,docker/docker,konstruktoid/docker-upstream,nawawi/docker,nalind/docker,cpuguy83/docker