don't run git fetch when not needed
don't run git fetch when not needed

otherwise get ugly error

raintank/metrictank,replay/metrictank,replay/metrictank,raintank/metrictank,raintank/metrictank,replay/metrictank,raintank/raintank-metric,raintank/raintank-metric,replay/metrictank,raintank/raintank-metric,raintank/metrictank