Elevate the write count during the vfs_rmdir() and vfs_unlink().

[AV: merged rmdir and unlink parts, added missing pieces in nfsd]
Acked-by: NSerge Hallyn <serue@us.ibm.com>
Acked-by: NAl Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDave Hansen <haveblue@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>