Fix go vet errors

Docker-DCO-1.1-Signed-off-by: Alexandr Morozov <lk4d4math@gmail.com> (github: LK4D4)

Docker-DCO-1.1-Signed-off-by: LK4D4 <lk4d4math@gmail.com> (github: vieux)
little more go vetting

Docker-DCO-1.1-Signed-off-by: Tibor Vass <teabee89@gmail.com> (github: tiborvass)
Merge pull request #5 from tiborvass/govet

Little more go vetting