ceph: improve caps debugging output

ceph: improve caps debugging output

This improves uniformity and exposes important sequence numbers.

Now looks like:

    <7>[   73.749563] ceph:           caps.c:4465 : [c9653bca-110b-4f70-9f84-5a195b205e9a 15290]  caps mds2 op export ino 20000000000.fffffffffffffffe inode 0000000008d2e5ea seq 0 iseq 0 mseq 0
    ...
    <7>[   73.749574] ceph:           caps.c:4102 : [c9653bca-110b-4f70-9f84-5a195b205e9a 15290]  cap 20000000000.fffffffffffffffe export to peer 1 piseq 1 pmseq 1
    ...
    <7>[   73.749645] ceph:           caps.c:4465 : [c9653bca-110b-4f70-9f84-5a195b205e9a 15290]  caps mds1 op import ino 20000000000.fffffffffffffffe inode 0000000008d2e5ea seq 1 iseq 1 mseq 1
    ...
    <7>[   73.749681] ceph:           caps.c:4244 : [c9653bca-110b-4f70-9f84-5a195b205e9a 15290]  cap 20000000000.fffffffffffffffe import from peer 2 piseq 686 pmseq 0
    ...
    <7>[  248.645596] ceph:           caps.c:4465 : [c9653bca-110b-4f70-9f84-5a195b205e9a 15290]  caps mds1 op revoke ino 20000000000.fffffffffffffffe inode 0000000008d2e5ea seq 2538 iseq 1 mseq 1

See also: "mds: add issue_seq to all cap messages" in ceph.git

See-also: https://tracker.ceph.com/issues/66704
Signed-off-by: Patrick Donnelly <pdonnell@redhat.com>