fix pre and post scripts to correctly create and delete the user

src/DEBIAN/control

@@ -1,5 +1,5 @@
 Package: kiosk-browser
-Version: 1.11
+Version: 1.12
 Priority: optional
 Section: universe/web
 Architecture: all

src/DEBIAN/postinst

@@ -2,14 +2,15 @@
 set -e 
 
 if ! getent passwd kiosk-browser >/dev/null; then
-        adduser --disabled-password --gecos "Kiosk Browser User" --firstuid 200 --lastuid 300 --home /var/lib/kiosk-browser kiosk-browser
+    useradd --system --user-group --comment "Kiosk Browser User" --no-create-home --home-dir /var/lib/kiosk-browser kiosk-browser
+    mkdir -p /var/lib/kiosk-browser
 fi
 
 # disable lightdm and enable nodm
 echo "/usr/sbin/nodm" >/etc/X11/default-display-manager
 # disable X cursor
 sed -i -e 's/NODM_X_OPTIONS=.*/NODM_X_OPTIONS="-nocursor -nolisten tcp"/' -e 's/NODM_ENABLED=.*/NODM_ENABLED=true/' -e 's/NODM_USER=.*/NODM_USER=kiosk-browser/' /etc/default/nodm
 
-# allow kiosk user to only write in chromium directories
+# allow kiosk user to only write in directories needed by chromium
 mkdir -p /var/lib/kiosk-browser/{.cache,.config/chromium,.pki}
 chown -R kiosk-browser:kiosk-browser /var/lib/kiosk-browser/{.cache,.config/chromium,.pki}

src/DEBIAN/postrm

@@ -1,8 +1,6 @@
 #!/bin/sh
 set -e
 
-if getent passwd kiosk-browser-g >/dev/null; then
-      	if [ -x /usr/sbin/deluser ]; then
-        	deluser --remove-home kiosk-browser || echo "Could not remove kiosk-browser user."
-	fi
+if getent passwd kiosk-browser >/dev/null; then
+     userdel --force --remove kiosk-browser || echo "Could not remove kiosk-browser user."
 fi