fix: rename vsftpd config file

/etc/init.d expects config files ending with *.conf to be special.

Change-Id: Idc20346eaec76150ca12ccbba73da1c3fdd67dac
fix: vsftpd conf file again, missed a spot

Change-Id: Ib5f30bc10667465d70fb06d04bec7313c8a8d33f