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: NMax Reitz <mreitz@redhat.com>
Reviewed-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

block/raw-posix.c

@@ -446,6 +446,7 @@ static int raw_open_common(BlockDriverState *bs, QDict *options,
     }
 
     if (fstat(s->fd, &st) < 0) {
+        ret = -errno;
         error_setg_errno(errp, errno, "Could not stat file");
         goto fail;
     }