Make BZflag script more robust

scripts/deploy_bzflag.sh

@@ -1,16 +1,23 @@
 #!/bin/bash
 set -e
 
+if [ -e /etc/systemd/system/bzflag.service ]; then
+  systemctl stop bzflag
+fi
+
 # Install BZFlag
 mkdir -p ${TMPDIR:-/tmp}/bzflag-build
 cd ${TMPDIR:-/tmp}/bzflag-build
+if [ -d bzflag ]; then
+  rm -rf bzflag
+fi
 git clone --branch ${bzflag_version} https://github.com/BZFlag-Dev/bzflag.git
 cd bzflag
 ./autogen.sh
 ./configure --disable-client --prefix=/opt/bzflag-${bzflag_version}
 make
 make install
-if [ -L /usr/games/bzfs ]; then
+if ! [ -L /usr/games/bzfs ]; then
   ln -s /opt/bzflag-2.4/bin/bzfs /usr/games/
 fi