Add an error debug message when disassociating part of a process
execution context using unshare fails.
As this is currently used to isolate a child process which is
immediately terminated silently if unshare fails, add a debug printout
and propagate up the error code to make the failure more visible.
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>