Check for default usernames

src/freedombone-config

@@ -734,8 +734,8 @@ function interactive_configuration {
         echo $'No user account was selected'
         exit 8347
     fi
-    if [[ $MY_USERNAME == 'debian' ]]; then
-        echo $"Don't use the default debian user account"
+    if [[ $MY_USERNAME == 'debian' || $MY_USERNAME == 'fbone' ]]; then
+        echo $"Don't use the default user account"
         exit 9341
     fi
     if [ ! -d /home/$MY_USERNAME ]; then