block/raw-posix: Fix ret in raw_open_common()

The return value must be negative on error; there is one place in
raw_open_common() where errp is set, but ret remains 0. Fix it.

Cc: qemu-stable@nongnu.org
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
(cherry picked from commit 01212d4)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>

block/raw-posix.c

@@ -447,6 +447,7 @@ static int raw_open_common(BlockDriverState *bs, QDict *options,
     s->has_write_zeroes = true;
 
     if (fstat(s->fd, &st) < 0) {
+        ret = -errno;
         error_setg_errno(errp, errno, "Could not stat file");
         goto fail;
     }