allocateNetwork: fix network sandbox not cleaned up on failure
allocateNetwork: fix network sandbox not cleaned up on failure

The defer function was checking for the local `err` variable, not
on the error that was returned by the function. As a result, the
sandbox would never be cleaned up for containers that used "none"
networking, and a failiure occured during setup.

Signed-off-by: Sebastiaan van Stijn <64b2b6d12bfe4baae7dad3d018f8cbf6b0e7a044@gone.nl>

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