This change ensures that updating the ldcache in a container also
includes the system search paths for the container ldconfig.

In most cases, the hook will be executing a host ldconfig that may be
configured widely differently from what the container image expects. The
common case is Debian-like (e.g. Debian, Ubuntu) vs non-Debian-like
(e.g. RHEL, Fedora). But there are also hosts that configure ldconfig
to search in a glibc prefix (e.g. /usr/lib/glibc). To avoid all these
cases, write the container's expected system search paths to a drop-in
conf file that is likely to be last in lexicographic order.
Entries in the top-level ld.so.conf file may be processed after this
drop-in, but this hook does not modify the top-level file if it exists.

Signed-off-by: Jean-Francois Roy <jeroy@nvidia.com>
Signed-off-by: Evan Lezar <elezar@nvidia.com>
(cherry picked from commit 6592021)