res_config_sqlite: Check for CDR unregistration failures

If the CDR unregistration fails due to an inflight CDR, the
res_config_sqlite module needs to bail on unloading itself. Otherwise,
the config could be unloaded (including the CDR table name) while the
CDR engine posts a CDR to the still registered backend, resulting in
a crash.
........

Merged revisions 403435 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@403436 65c4cc65-6c06-0410-ace0-fbb531ad65f3

res/res_config_sqlite.c

@@ -1627,11 +1627,13 @@ static char *handle_cli_sqlite_show_tables(struct ast_cli_entry *e, int cmd, str
 
 static int unload_module(void)
 {
-	if (cli_status_registered)
-		ast_cli_unregister_multiple(cli_status, ARRAY_LEN(cli_status));
+	if (cdr_registered && ast_cdr_unregister(RES_CONFIG_SQLITE_NAME)) {
+		return -1;
+	}
 
-	if (cdr_registered)
-		ast_cdr_unregister(RES_CONFIG_SQLITE_NAME);
+	if (cli_status_registered) {
+		ast_cli_unregister_multiple(cli_status, ARRAY_LEN(cli_status));
+	}
 
 	ast_config_engine_deregister(&sqlite_engine);