In RFC3530, the RENEW operation is allowed to use either

 the same principal, RPC security flavour and (if RPCSEC_GSS), the same
  mechanism and service that was used for SETCLIENTID_CONFIRM

 OR

 Any principal, RPC security flavour and service combination that
 currently has an OPEN file on the server.

 Choose the latter since that doesn't require us to keep credentials for
 the same principal for the entire duration of the mount.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

 - Move NFSv4 state definitions into a private header file.
 - Clean up gunk in nfs_fs.h
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!