Compute checksum after possible in-place sed changes

target/start-mailserver.sh

@@ -89,7 +89,6 @@ function register_functions() {
 	################### >> setup funcs
 
 	_register_setup_function "_setup_default_vars"
-	_register_setup_function "_setup_chksum_file"
 
 	if [ "$ENABLE_ELK_FORWARDER" = 1 ]; then
 		_register_setup_function "_setup_elk_forwarder"
@@ -167,6 +166,9 @@ function register_functions() {
   	_register_setup_function "_setup_mail_summary"
   fi
 
+        # Compute last as the config files are modified in-place
+        _register_setup_function "_setup_chksum_file"
+
 	################### << setup funcs
 
 	################### >> fix funcs