Fixing user namespaces (again) with a vendor update from runc
(specifically, the remount() only if special flags change)
Other changes are very minimal.
Docker-DCO-1.1-Signed-off-by: Phil Estes <estesp@linux.vnet.ibm.com> (github: estesp)
Upstream-commit: b7a009cc1c9747cab4ebf40e609068c86f34d19d
Component: engine