[gimp] app: conditionnally free new profile in gimp_image_convert_precision().

[Jehan <jehanp src gnome org>]

commit ea67537d859ee415e7cc0c0666a152b29e458d09
Author: Jehan <jehan girinstud io>
Date:   Mon Sep 10 15:54:09 2018 +0200

    app: conditionnally free new profile in gimp_image_convert_precision().
    
    Do not free a NULL pointer! This fixes a CRITICAL:
    > g_object_unref: assertion 'G_IS_OBJECT (object)' failed

 app/core/gimpimage-convert-precision.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)
---
diff --git a/app/core/gimpimage-convert-precision.c b/app/core/gimpimage-convert-precision.c
index bcf11186b9..04e6b6efc6 100644
--- a/app/core/gimpimage-convert-precision.c
+++ b/app/core/gimpimage-convert-precision.c
@@ -191,11 +191,14 @@ gimp_image_convert_precision (GimpImage        *image,
     }
 
   if (new_profile)
-    gimp_image_set_color_profile (image, new_profile, NULL);
+    {
+      gimp_image_set_color_profile (image, new_profile, NULL);
+      g_object_unref (new_profile);
+    }
   else
-    gimp_color_managed_profile_changed (GIMP_COLOR_MANAGED (image));
-
-  g_object_unref (new_profile);
+    {
+      gimp_color_managed_profile_changed (GIMP_COLOR_MANAGED (image));
+    }
 
   gimp_image_undo_group_end (image);