Improve encfs cookbook

Fix some things, and prepare for path-based activation. Also, comment
the buggy initial dir creation and explain manual provisioning in README
for now.

site-cookbooks/kosmos_encfs/templates/mount_encfs.erb

@@ -1,3 +1,4 @@
 #!/bin/sh
 
 systemd-ask-password --echo "encfs password:" | encfs <%= @encrypted_directory %> <%= @mount_directory %> --public --stdinpass
+echo "Encrypted data directory mounted as <%= @mount_directory %>" > /tmp/data-dir-mounted.txt

site-cookbooks/kosmos_encfs/templates/systemd_unit.path.erb

@@ -0,0 +1,9 @@
+[Unit]
+Description=Start <%= @service_unit %> when encrypted data directory is mounted
+
+[Path]
+PathExists=/tmp/data-dir-mounted.txt
+Unit=<%= @service_unit %>
+
+[Install]
+WantedBy=multi-user.target

site-cookbooks/kosmos_encfs/templates/unmount_encfs.erb

@@ -0,0 +1,4 @@
+#!/bin/sh
+
+rm /tmp/data-dir-mounted.txt
+/bin/umount <%= @mount_directory %>