refactor: use hostname instead of variable

enter.sh

@@ -13,6 +13,7 @@ arg() { echo -n " $@"; }
 # starting a new container.
 run_args() {
   arg "--name $name"
+  arg "--hostname $name"
 
   # Disable some security settings so host directories can
   # be mounted without problems.
@@ -23,7 +24,6 @@ run_args() {
   # container.
   [ -e "/run/user/$UID/bus" ] && arg "-v /run/user/$UID/bus:/tmp/bus" # Use host dbus.
   arg "-e HOST_HOME=$HOME"                                            # Used to translate container path to host.
-  arg "-e CONTAINER_NAME=$name"
 
   # Use host networking.
   arg "--net=host"