Add better error handling

roles/fai/templates/srv/fai/config/scripts/00-remove-proxy.j2

@@ -1,5 +1,5 @@
 #!/bin/bash
 
 [ -f $target/etc/apt/apt.conf.d/02proxy ] && \
-        rm $target/etc/apt/apt.conf.d/02proxy
+        $ROOTCMD rm -v /etc/apt/apt.conf.d/02proxy
 

roles/fai/templates/srv/fai/config/scripts/04-snaps

@@ -1,5 +1,7 @@
 #!/bin/bash
 
+error=0; trap 'error=$(($?>$error?$?:$error))'
+
 ### FAILS: snapd is not running during FAI
 
 if [ "${#SNAPS[*]}" -eq 0 ]; then

roles/fai/templates/srv/fai/config/scripts/91-misc

@@ -1,7 +1,11 @@
 #! /bin/bash
 
+error=0; trap 'error=$(($?>$error?$?:$error))'
+
 # disable the first login screen
 $ROOTCMD dpkg-divert --local --rename --add /etc/xdg/autostart/gnome-initial-setup-first-login.desktop
 $ROOTCMD dpkg-divert --local --rename --add /etc/xdg/autostart/gnome-initial-setup-copy-worker.desktop
 $ROOTCMD deluser --system gnome-initial-setup
 $ROOTCMD dpkg-reconfigure keyboard-configuration
+
+exit $error