[devhelp] Book: set_enabled(): sanitize gboolean input

[Sébastien Wilmet <swilmet src gnome org>]

commit 076d735875887778b7d9528671fd9512ff8ea741
Author: Sébastien Wilmet <swilmet gnome org>
Date:   Sun Dec 10 11:46:30 2017 +0100

    Book: set_enabled(): sanitize gboolean input
    
    It's especially important since priv->enabled is a bit field in the
    struct.

 src/dh-book.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/src/dh-book.c b/src/dh-book.c
index c009e97..fbe8b23 100644
--- a/src/dh-book.c
+++ b/src/dh-book.c
@@ -551,6 +551,9 @@ dh_book_set_enabled (DhBook   *book,
         g_return_if_fail (DH_IS_BOOK (book));
 
         priv = dh_book_get_instance_private (book);
+
+        enabled = enabled != FALSE;
+
         if (priv->enabled != enabled) {
                 priv->enabled = enabled;
                 g_signal_emit (book,