ceph.in: try harder if asok path does not exist

ceph.in: try harder if asok path does not exist

when handling "ceph daemon <name> ...", we need to figure out the asok
path, if the "<name>" option is not a path but a "name" as it claims to
be. but if the "admin_socket" option includes substitution/meta variable of
"$pid", it will be expanded using its own pid, instead of the process
with the specified "name". but "ceph" cli does not offer a dedicated
option for overriding the pid for ceph-conf which is used "ceph" cli to
retrieve the "admin_socket" option with specified "name".

in this change, "<name>" option is interpreted as "${name}.${pid}" if
the returned admin_socket path does not point to a valid UNIX domain
socket file. and "ceph" cli will try harder by passing "--pid ${pid}"
and "--name ${name}" instead of "--name ${name}.${pid}" to ceph-conf.

Fixes: https://tracker.ceph.com/issues/47977
Signed-off-by: Kefu Chai <kchai@redhat.com>