TAKE - Backport an nfsd fix from 2.4.0-test2.

[Ted Kline <jtk@xxxxxxx>]

Now I can unexport and unmount an XFS filesystem after it'd
been used/exported via NFS.


Date:  Thu Jul  6 15:44:18 PDT 2000
Workarea:  tiki.cray.com:/data/clink/io/jtk/work-linux2.4-test1

The following file(s) were checked into:
  bonnie.engr.sgi.com:/isms/slinx/2.4.0-test1-xfs


Modid:  2.4.0-test1-xfs:slinx:66068a
linux/fs/nfsd/export.c - 1.14
http://oss.sgi.com/cgi-bin/cvsweb.cgi/linux-2.4-xfs/linux/fs/nfsd/export.c.diff?r1=text&tr1=1.14&r2=text&tr2=1.13&f=h
        - Backport a fix from 2.4.0-test2, exp_export was keeping one too
          many ref's on the mount table entry, this was getting in the
          way of the XFS/NFS testing.