res_pjsip_pubsub: Treat "prune_on_boot" as a yes / no.

The alembic for the PJSIP subscription persistence table has the
"prune_on_boot" field as a boolean. While in Asterisk we are
tolerant of many different definitions of true and false in the
database we only accept "yes" and "no". This change makes the
field treated as a yes/no instead of an integer, thus storing
"yes" and "no" instead of "1" and "0".

Change-Id: Ic8b9211b36babefe78f70def6828a135a6ae7ab6

res/res_pjsip_pubsub.c

@@ -5589,7 +5589,7 @@ static int load_module(void)
 		persistence_expires_str2struct, persistence_expires_struct2str, NULL, 0, 0);
 	ast_sorcery_object_field_register(sorcery, "subscription_persistence", "contact_uri", "", OPT_CHAR_ARRAY_T, 0,
 		CHARFLDSET(struct subscription_persistence, contact_uri));
-	ast_sorcery_object_field_register(sorcery, "subscription_persistence", "prune_on_boot", "0", OPT_UINT_T, 0,
+	ast_sorcery_object_field_register(sorcery, "subscription_persistence", "prune_on_boot", "no", OPT_YESNO_T, 0,
 		FLDSET(struct subscription_persistence, prune_on_boot));
 
 	if (apply_list_configuration(sorcery)) {