kclient: link snap dentry for MKSNAP as well as LOOKUPSNAP
kclient: link snap dentry for MKSNAP as well as LOOKUPSNAP

Also, set is_dentry = 1 to prevent the notrace handler(s) from doing
another lookup.

ajnelson/ceph,ajnelson/ceph,ajnelson/ceph,ajnelson/ceph,ajnelson/ceph,ajnelson/ceph