[Trusty SRU/3.13.y stable] Fix 16s delay when mounting NFS

[Stefan Bader]

When mounting NFS mounts and not using kerberos authentication (which
meant gssd is not running), we currently run into a 16s delay if the
NFSv3 protocol isn not enforced (-onfsvers=3).

This was fixed upstream in 3.14, so no other stable likely is affected
and cares.

The fix required cherry-picking another two patches that introduced the
method of figuring out whether gssd is running or not. I could check that
at least the mount without kerberos authentication is working and not
showing any delay with those applied.

-Stefan