Fork-exec new{u,g}idmap instead of shelling out
Fork-exec new{u,g}idmap instead of shelling out

Signed-off-by: Ed King <cb0ef010d3b7764b76e01d19f7526ae755120a2b@pivotal.io>
Signed-off-by: Georgi Sabev <cd7643e50243a10153b49cb72b4bdbf8b48cb045@gmail.com>

cloudfoundry-incubator/runc,cloudfoundry-incubator/runc,cloudfoundry-incubator/runc