Fixes #505. fix the bug in toggle_sftp to correctly replace/populate the subsystem line.
use lsblk to even identify existing btrfs filesystems.
restart ssh when reload doesn't work as the service is not running in the first place.
Merge pull request #508 from schakrava/issue#505_sftp_bug

Issue#505 sftp bug
comments should start with ; and afp.conf must be readable by non-root users.