orangefs: do not check possibly stale size on truncate

Let the server figure this out because our size might be out of date or
not present.

The bug was that

	xfs_io -f -t -c "pread -v 0 100" /mnt/foo
	echo "Test" > /mnt/foo
	xfs_io -f -t -c "pread -v 0 100" /mnt/foo

fails because the second truncate did not happen if nothing had
requested the size after the write in echo.  Thus i_size was zero (not
present) and the orangefs_setattr though i_size was zero and there was
nothing to do.
Signed-off-by: Martin Brandenburg <martin@omnibond.com>
Cc: stable@vger.kernel.org
Signed-off-by: Mike Marshall <hubcap@omnibond.com>

fs/orangefs/inode.c

@@ -218,8 +218,7 @@ int orangefs_setattr(struct dentry *dentry, struct iattr *iattr)
 	if (ret)
 		goto out;
 
-	if ((iattr->ia_valid & ATTR_SIZE) &&
-	    iattr->ia_size != i_size_read(inode)) {
+	if (iattr->ia_valid & ATTR_SIZE) {
 		ret = orangefs_setattr_size(inode, iattr);
 		if (ret)
 			goto out;