[glom] Remove unnecessary glibmm/thread.h include.

[Murray Cumming <murrayc src gnome org>]

commit 8f63d43b86d61abc7a8ab888711f7a3ba678d0e2
Author: Murray Cumming <murrayc murrayc com>
Date:   Fri Dec 16 13:35:02 2016 +0100

    Remove unnecessary glibmm/thread.h include.

 glom/libglom/spawn_with_feedback.cc |    1 -
 1 files changed, 0 insertions(+), 1 deletions(-)
---
diff --git a/glom/libglom/spawn_with_feedback.cc b/glom/libglom/spawn_with_feedback.cc
index f1b7c07..5adf566 100644
--- a/glom/libglom/spawn_with_feedback.cc
+++ b/glom/libglom/spawn_with_feedback.cc
@@ -18,7 +18,6 @@
  * Boston, MA 02110-1301 USA.
  */
 
-#include <glibmm/thread.h>
 #include <libglom/spawn_with_feedback.h>
 #include <glibmm/main.h>
 #include <glibmm/spawn.h>