smb: client: fix oops due to uninitialised var in smb2_unlink()

If SMB2_open_init() or SMB2_close_init() fails (e.g. reconnect), the
iovs set @rqst will be left uninitialised, hence calling
SMB2_open_free(), SMB2_close_free() or smb2_set_related() on them will
oops.

Fix this by initialising @close_iov and @open_iov before setting them
in @rqst.

Reported-by: Thiago Becker <[e-mail]>
Fixes: 1cf9f2a6a544 ("smb: client: handle unlink(2) of files open by different clients")
Signed-off-by: Paulo Alcantara (Red Hat) <[e-mail]>
Cc: David Howells <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Signed-off-by: Steve French <[e-mail]>

fs/smb/client/smb2inode.c

···
 	memset(resp_buftype, 0, sizeof(resp_buftype));
 	memset(rsp_iov, 0, sizeof(rsp_iov));
 
+	memset(open_iov, 0, sizeof(open_iov));
 	rqst[0].rq_iov = open_iov;
 	rqst[0].rq_nvec = ARRAY_SIZE(open_iov);
 
···
 	creq = rqst[0].rq_iov[0].iov_base;
 	creq->ShareAccess = FILE_SHARE_DELETE_LE;
 
+	memset(&close_iov, 0, sizeof(close_iov));
 	rqst[1].rq_iov = &close_iov;
 	rqst[1].rq_nvec = 1;
 
 	rc = SMB2_close_init(tcon, server, &rqst[1],
 			     COMPOUND_FID, COMPOUND_FID, false);
-	smb2_set_related(&rqst[1]);
 	if (rc)
 		goto err_free;
+	smb2_set_related(&rqst[1]);
 
 	if (retries) {
 		/* Back-off before retry */