A few vet and errchk issues that could be fixed

[tomdee]

docker run --rm \
	-e LOCAL_USER_ID=1001 \
	-v /home/tom/go/src/github.com/projectcalico/calico-bgp-daemon:/go/src/github.com/projectcalico/calico-bgp-daemon \
	calico/go-build:v0.16 sh -c '\
		cd  /go/src/github.com/projectcalico/calico-bgp-daemon && \
		gometalinter --deadline=300s --disable-all --enable=goimports --enable=vet --enable=errcheck --vendor -s gobgp ./...'
Starting with UID : 1001
ipam.go:176::error: unreachable code (vet)
main.go:382::error: missing argument for Errorf("%s"): format reads arg 1, have only 0 args (vet)
k8s.go:128:14:warning: error return value not checked (p.ipam.sync()) (errcheck)
k8s.go:129:26:warning: error return value not checked (p.k8scli.checkBGPConfig()) (errcheck)
main.go:154:19:warning: error return value not checked (netlink.RouteDel(&route)) (errcheck)
Makefile:162: recipe for target 'static-checks' failed
make: *** [static-checks] Error 1