[epiphany] header-bar: Fix middle click action for forward/back buttons

[Michael Catanzaro <mcatanzaro src gnome org>]

commit 905936babce66637b22f783c099648b35ad93a9e
Author: Mal <malbx 00 gmail com>
Date:   Fri Nov 10 22:16:14 2017 -0500

    header-bar: Fix middle click action for forward/back buttons
    
    https://bugzilla.gnome.org/show_bug.cgi?id=790017

 src/ephy-header-bar.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/src/ephy-header-bar.c b/src/ephy-header-bar.c
index eef7a16..389c34b 100644
--- a/src/ephy-header-bar.c
+++ b/src/ephy-header-bar.c
@@ -502,8 +502,8 @@ navigation_button_release_event_cb (GtkButton *button,
   action_name = gtk_actionable_get_action_name (GTK_ACTIONABLE (button));
   action_group = gtk_widget_get_action_group (GTK_WIDGET (header_bar->window), "toolbar");
 
-  direction = strstr (action_name, "back") == 0 ? EPHY_NAVIGATION_HISTORY_DIRECTION_BACK
-                                                : EPHY_NAVIGATION_HISTORY_DIRECTION_FORWARD;
+  direction = strcmp (action_name, "toolbar.navigation-back") == 0 ? EPHY_NAVIGATION_HISTORY_DIRECTION_BACK
+                                                                   : 
EPHY_NAVIGATION_HISTORY_DIRECTION_FORWARD;
 
   switch (((GdkEventButton *)event)->button) {
     case GDK_BUTTON_MIDDLE: