[gnome-photos] Fix distcheck

[Debarshi Ray <debarshir src gnome org>]

commit 254152a1d957ac5160276b0b1da097c5562254f9
Author: Debarshi Ray <debarshir gnome org>
Date:   Wed Jun 7 21:36:50 2017 +0200

    Fix distcheck
    
    Fallout from fa0756e6edf68c5796759d6b3a6f09216ec4f8b1

 src/Makefile.am |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/src/Makefile.am b/src/Makefile.am
index 6bf99ef..b0b0936 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -354,6 +354,7 @@ EXTRA_DIST = \
        photos-embed.ui \
        photos-export-dialog.ui \
        photos-help-overlay.ui \
+       photos-main-toolbar.ui \
        photos-main-window.ui \
        photos-marshalers.list \
        photos-menus.ui \