Revert "don't include vendor dir in go vet"
Revert "don't include vendor dir in go vet"

This reverts commit e00dca9c720f20bbfb4f91795c97f3701df44cd7.

raintank/raintank-metric,OOM-Killer/metrictank,replay/metrictank,raintank/raintank-metric,OOM-Killer/metrictank,raintank/metrictank,raintank/metrictank,OOM-Killer/metrictank,replay/metrictank,raintank/metrictank,raintank/raintank-metric,replay/metrictank,replay/metrictank,raintank/metrictank