[libchamplain] Make launcher-gtk.py Python 3 compatible

[Jiří Techet <jiritechet src gnome org>]

commit 71b6d8ce27070f51c315411ec8af68672254b20f
Author: Chris Mayo <aklhfex gmail com>
Date:   Sat Aug 12 11:27:23 2017 +0100

    Make launcher-gtk.py Python 3 compatible
    
    https://bugzilla.gnome.org/show_bug.cgi?id=786195

 demos/launcher-gtk.py |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/demos/launcher-gtk.py b/demos/launcher-gtk.py
index d5b4103..7b36b01 100755
--- a/demos/launcher-gtk.py
+++ b/demos/launcher-gtk.py
@@ -122,7 +122,7 @@ class LauncherGTK:
     def mouse_click_cb(self, actor, event, view):
         x, y = event.x, event.y
         lon, lat = view.x_to_longitude(x), view.y_to_latitude(y)
-        print "Mouse click at: %f %f" % (lat, lon)
+        print("Mouse click at: %f %f" % (lat, lon))
         return True
 
     def zoom_changed(self, widget):
@@ -150,7 +150,7 @@ class LauncherGTK:
         if event.button != 1 and event.click_count > 1:
             return False
 
-        print "Montreal was clicked\n"
+        print("Montreal was clicked\n")
         return True