GUACAMOLE-374: Enable automatic IP banning (brute-force throttling) b…

…y default.

Dockerfile

@@ -97,8 +97,9 @@ RUN useradd --system --create-home --shell /usr/sbin/nologin --uid $UID --gid $G
 USER guacamole
 
 # Environment variable defaults
-ENV GUACAMOLE_HOME=/etc/guacamole \
-    ENABLE_FILE_ENVIRONMENT_PROPERTIES=true
+ENV BAN_ENABLED=true \
+    ENABLE_FILE_ENVIRONMENT_PROPERTIES=true \
+    GUACAMOLE_HOME=/etc/guacamole
 
 # Start Guacamole under Tomcat, listening on 0.0.0.0:8080
 EXPOSE 8080