ODLPARENT-139: re-use caches when restarting

ODLPARENT-139: re-use caches when restarting

When the Shiro bundles restart, for whatever reason, they always
attempt to re-create their caches; that fails because the caches are
still present. This patch re-uses existing cache managers and caches
when possible.

This doesn’t entirely resolve the SSH issues reported in
ODLPARENT-139, but it helps the SSH connection survive longer (which
makes it easier to debug).

Change-Id: I27944a87cfbd78b385274dee0c7c17b9aac4dd58
Signed-off-by: Stephen Kitt <skitt@redhat.com>