daemon-unix: Fix leak of a fork error message.

19 bytes in 1 blocks are definitely lost in loss record 24 of 121
    at 0x4839748: malloc (vg_replace_malloc.c:306)
    by 0x483BD63: realloc (vg_replace_malloc.c:834)
    by 0x521C26: xrealloc (util.c:149)
    by 0x478F91: ds_reserve (dynamic-string.c:63)
    by 0x47928B: ds_put_format_valist (dynamic-string.c:161)
    by 0x47920A: ds_put_format (dynamic-string.c:142)
    by 0x506DE5: process_status_msg (process.c:0)
    by 0x52A6D0: fork_and_wait_for_startup (daemon-unix.c:284)
    by 0x52A54D: daemonize_start (daemon-unix.c:453)
    by 0x40EB3E: main (ovs-vswitchd.c:91)

Fixes: b925336 ("daemon: restart child process if it died before signaling its readiness")
Signed-off-by: Ilya Maximets <[email protected]>
Acked-by: Roi Dayan <[email protected]>

lib/daemon-unix.c

@@ -285,6 +285,7 @@ fork_and_wait_for_startup(int *fdp, pid_t *child_pid)
                     VLOG_ERR("fork child died before signaling startup (%s)",
                              status_msg);
                     ret = -1;
+                    free(status_msg);
                 }
             } else if (retval < 0) {
                 VLOG_FATAL("waitpid failed (%s)", ovs_strerror(errno));