NFSv4: Map NFS4ERR_SHARE_DENIED into an EACCES error instead of EIO
If a file OPEN is denied due to a share lock, the resulting
NFS4ERR_SHARE_DENIED is currently mapped to the default EIO.
This patch adds a more appropriate mapping, and brings Linux
into line with what Solaris 10 does.
See https://bugzilla.kernel.org/show_bug.cgi?id=43286