connpool: disallow pushing nil connections to the connpool.
connpool: disallow pushing nil connections to the connpool.

trigrass2/radix,mediocregopher/radix.v2,gabrielperezs/radix.improved,beni55/radix,rightscale/radix,ctrlaltdel121/radix,mediocregopher/radix.v3,bpowers/radix,alphagov/radix,bpowers/radix,fzzy/radix