[gnome-flashback] monitor-config-manager: fix implicit conversion warning

[Alberts Muktupāvels <muktupavels src gnome org>]

commit 1673742fea176af743613fe39bb08eb98e3f7afd
Author: Alberts Muktupāvels <alberts muktupavels gmail com>
Date:   Wed Jan 24 17:04:06 2018 +0200

    monitor-config-manager: fix implicit conversion warning

 backends/gf-monitor-config-manager.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/backends/gf-monitor-config-manager.c b/backends/gf-monitor-config-manager.c
index 11aa638..ff196a6 100644
--- a/backends/gf-monitor-config-manager.c
+++ b/backends/gf-monitor-config-manager.c
@@ -598,7 +598,7 @@ assign_monitor_crtcs (GfMonitorManager        *manager,
       g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
                    "Invalid mode %dx%d (%f) for monitor '%s %s'",
                    monitor_mode_spec->width, monitor_mode_spec->height,
-                   monitor_mode_spec->refresh_rate,
+                   (gdouble) monitor_mode_spec->refresh_rate,
                    monitor_spec->vendor, monitor_spec->product);
 
       return FALSE;