gl: display: demote error level at display creation error

https://bugzilla.gnome.org/show_bug.cgi?id=791391

gst-libs/gst/gl/egl/gstgldisplay_egl.c

@@ -185,7 +185,7 @@ gst_gl_display_egl_new (void)
       gst_gl_display_egl_get_from_native (GST_GL_DISPLAY_TYPE_ANY, 0);
 
   if (!ret->display) {
-    GST_ERROR ("Failed to open EGL display connection");
+    GST_INFO ("Failed to open EGL display connection");
   }
 
   return ret;

gst-libs/gst/gl/wayland/gstgldisplay_wayland.c

@@ -128,7 +128,7 @@ gst_gl_display_wayland_new (const gchar * name)
       GST_ERROR ("Failed to open Wayland display connection with name \'%s\'",
           name);
     } else {
-      GST_ERROR ("Failed to open Wayland display connection.");
+      GST_INFO ("Failed to open Wayland display connection.");
     }
     return NULL;
   }

gst-libs/gst/gl/x11/gstgldisplay_x11.c

@@ -95,7 +95,7 @@ gst_gl_display_x11_new (const gchar * name)
   ret->display = XOpenDisplay (ret->name);
 
   if (!ret->display) {
-    GST_ERROR ("Failed to open X11 display connection with name, \'%s\'", name);
+    GST_INFO ("Failed to open X11 display connection with name, \'%s\'", name);
     gst_object_unref (ret);
     return NULL;
   }