[devhelp] Book: update a comment after DhBookManager changes

[Sébastien Wilmet <swilmet src gnome org>]

commit bd8b626a64a2a5275505c8ef346d9838ae684b7d
Author: Sébastien Wilmet <swilmet gnome org>
Date:   Mon Apr 30 17:48:11 2018 +0200

    Book: update a comment after DhBookManager changes

 devhelp/dh-book.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)
---
diff --git a/devhelp/dh-book.c b/devhelp/dh-book.c
index f3ee64f..72071a2 100644
--- a/devhelp/dh-book.c
+++ b/devhelp/dh-book.c
@@ -277,9 +277,9 @@ dh_book_new (GFile *index_file)
                                    &priv->tree,
                                    &priv->links,
                                    &error)) {
-                /* It's fine if the file doesn't exist, as DhBookManager tries
-                 * to create a DhBook for each possible index file in a certain
-                 * book directory.
+                /* It's fine if the file doesn't exist, because
+                 * DhBookListDirectory tries to create a DhBook for each
+                 * possible index file in a certain book directory.
                  */
                 if (error != NULL &&
                     !g_error_matches (error, G_IO_ERROR, G_IO_ERROR_NOT_FOUND)) {