GUACAMOLE-637: Replace usages of strncat() with guac_strlcat().
GUACAMOLE-637: Replace usages of strncat() with guac_strlcat().

mike-jumper/incubator-guacamole-server,glyptodon/guacamole-server,glyptodon/guacamole-server,glyptodon/guacamole-server,mike-jumper/incubator-guacamole-server,apache/guacamole-server,mike-jumper/incubator-guacamole-server,apache/guacamole-server,apache/guacamole-server,mike-jumper/incubator-guacamole-server