libweston: make session_active a bool

compositor->session_active should be a bool as it tracks a boolean
condition.

Signed-off-by: Robert Beckett <bob.beckett@collabora.com>
diff --git a/libweston/compositor.c b/libweston/compositor.c
index deb2edd..848ae4e 100644
--- a/libweston/compositor.c
+++ b/libweston/compositor.c
@@ -7195,7 +7195,7 @@
 	wl_signal_init(&ec->heads_changed_signal);
 	wl_signal_init(&ec->output_heads_changed_signal);
 	wl_signal_init(&ec->session_signal);
-	ec->session_active = 1;
+	ec->session_active = true;
 
 	ec->output_id_pool = 0;
 	ec->repaint_msec = DEFAULT_REPAINT_WINDOW;