daemon/monitor: rm redundant if
daemon/monitor: rm redundant if

The last check for err != nil is not needed as err is always non-nil
there. Remove the check.

Also, no need to explicitly define `var err error` here.

Signed-off-by: Kir Kolyshkin <3a017b8ddb3f9cf3e4a59978b004111bdeb97f08@gmail.com>

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