c/r: populate clone flags on restore

c/r: populate clone flags on restore

Since attach asks the restore process what the clone flags were, if we forgot
to set them then the attach command ran in the hosts namespaces instead of the
containers, which is a Very Bad Thing :). Instead, we remember to set the clone
flags in the restore process' handler, so that we report them correctly to any
attach processes who ask.

Signed-off-by: Tycho Andersen <tycho.andersen@canonical.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>