Delete example passwords.txt file that hasn't been needed in weeks

sbws/passwords.txt.example

-# All lines that don't start with '#' must be valid passwords.
-# Use only basic ASCII characters.
-#
-# You can use the following command to add a new password.
-# (</dev/urandom tr -dc 'a-zA-Z0-9' | head -c 64; echo '') | tee -a passwords.txt
-#
-# Clients will use the first non-comment line as their password.
-# Servers will accept all non-comment lines as valid passwords.
-#
-# Passwords must be the width of the following line.
-################################################################