commit 93d8690481f2a09904f528ea5f01099cdd5dfbed
Author: Andrew Beekhof <andrew@beekhof.net>
Date:   Tue Aug 6 12:42:12 2013 +1000

    Fix: systemd: Prevent glib assertion - only call g_error_free() with non-NULL arguments

diff --git a/lib/services/systemd.c b/lib/services/systemd.c
index 2a66da5..b18f86f 100644
--- a/lib/services/systemd.c
+++ b/lib/services/systemd.c
@@ -478,7 +478,10 @@ systemd_unit_exec(svc_action_t * op, gboolean synchronous)
             fclose(file_strm);
         }
         systemd_daemon_reload(systemd_proxy, &error);
-        g_error_free(error); error = NULL;
+        if(error) {
+            g_error_free(error);
+            error = NULL;
+        }
         free(override_file);
         free(override_dir);