Add clarity for error on missing management paramater. (#657)

Configuration files located in config-auto require a management parameter to be declared.

res/openvpn-gui-res-en.rc

@@ -425,7 +425,8 @@ View log file (%ls) for more details."
     IDS_NFO_SERVICE_STOPPED "OpenVPN Service stopped."
     IDS_NFO_ACTIVE_CONN_EXIT "There are still active connections that will be closed if you exit OpenVPN GUI.\
 \n\nAre you sure you want to exit?"
-    IDS_ERR_PARSE_MGMT_OPTION "Could not parse --management option in <%ls%ls>."
+    IDS_ERR_PARSE_MGMT_OPTION "Could not parse --management option in <%ls%ls>. \
+Attaching to auto-started connections require --management option in the config file."
     IDS_NFO_SERVICE_ACTIVE_EXIT "You are currently connected (the OpenVPN Service is running). \
 You will stay connected even if you exit OpenVPN GUI.\n\n\
 Do you want to proceed and exit OpenVPN GUI?"