[gnome-desktop-testing] cancel_test(): Fix sd_journal_send format string

[Colin Walters <walters src gnome org>]

commit cdab3090b14a62253bd28b4e8c89297c021029e6
Author: Colin Walters <walters verbum org>
Date:   Tue Oct 24 14:12:49 2017 -0400

    cancel_test(): Fix sd_journal_send format string
    
    Saw this in a libostree PR, was caught by ASAN there.

 src/gnome-desktop-testing-runner.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/gnome-desktop-testing-runner.c b/src/gnome-desktop-testing-runner.c
index a610748..53663b8 100644
--- a/src/gnome-desktop-testing-runner.c
+++ b/src/gnome-desktop-testing-runner.c
@@ -397,7 +397,7 @@ cancel_test (gpointer data)
 {
   GSubprocess*proc = data;
   g_subprocess_force_exit (proc);
-  sd_journal_send ("MESSAGE_ID=%s" ONE_TEST_TIMED_OUT_MSGID,
+  sd_journal_send ("MESSAGE_ID=%s", ONE_TEST_TIMED_OUT_MSGID,
                    "MESSAGE=Test timed out after %u seconds",
                    opt_cancel_timeout,
                    NULL);