add LocaleGuards to 2 places where we save pane sizes (which are floating point values now)

gtk2_ardour/editor.cc

@@ -2579,6 +2579,7 @@ Editor::get_state ()
 {
 	XMLNode* node = new XMLNode (X_("Editor"));
 	char buf[32];
+	LocaleGuard lg;
 
 	id().print (buf, sizeof (buf));
 	node->add_property ("id", buf);

gtk2_ardour/mixer_ui.cc

@@ -1924,6 +1924,7 @@ Mixer_UI::get_state ()
 {
 	XMLNode* node = new XMLNode (X_("Mixer"));
 	char buf[128];
+	LocaleGuard lg;
 
 	node->add_child_nocopy (Tabbable::get_state());