oracle template: fixes for older releases

This fixes some issues found by Oracle QA, including several cosmetic
errors seen during container bootup.

The rpm database needs moving on Debian hosts similar to on Ubuntu.

I took Serge's suggestions: Do the yum install in an unshared
mount namespace so the /proc mount done during OL4 install doesn't
pollute the host. No need to blacklist ipv6 modules.

Make the default release 6.3, unless the host is OL, then default
to the same version as the host (same as Ubuntu template does).

Signed-off-by: Dwight Engen <dwight.engen@oracle.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
Add lxc.stopsignal config option

I remember discussion about implementing proper way to shutdown
guests using different signals, so here's a patch proposal.
It allows to use specific signal numbers to shutdown guests
gracefully, for example SIGRTMIN+4 starts poweroff.target in
systemd.

Signed-off-by: Alexander Vladimirov <alexander.idkfa.vladimirov@gmail.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
uidmap: fix writing multiple ranges

The kernel requires a single atomic write for setting the /proc
idmap files. We were calling write(2) more than once when multiple
ranges were configured so instead build a buffer to pass in one write(2)
call.

Change id types to unsigned long to handle large id mappings gracefully.

Fix max id in example comment.

Signed-off-by: Dwight Engen <dwight.engen@oracle.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>