exec_close(): accept any negative value as qemu_fclose() error

Note that we don't return the unchanged return value back yet, because
we need to change all qemu_fclose() callers to accept any positive value
as success.
Signed-off-by: NEduardo Habkost <ehabkost@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

migration-exec.c

@@ -50,7 +50,7 @@ static int exec_close(MigrationState *s)
         ret = qemu_fclose(s->opaque);
         s->opaque = NULL;
         s->fd = -1;
-        if (ret != -1 &&
+        if (ret >= 0 &&
             WIFEXITED(ret)
             && WEXITSTATUS(ret) == 0) {
             ret = 0;