init: Make encryption action an argument to mkdir

FscryptSetDirectoryPolicy no longer tries to infer the action from the
filename. Well mostly; it still assumes top-level directories in /data
should be encrypted unless the mkdir arguments say otherwise, but
it warns.

Bug: 26641735
Test: boot, check log messages
Change-Id: Id6d2cea7fb856f17323897d85cf6190c981b443c

prebuilt/common/etc/init/lineage-ssh.rc

@@ -1,3 +1,3 @@
 on post-fs-data
-    mkdir /data/ssh 0750 root shell
+    mkdir /data/ssh 0750 root shell encryption=Require
     mkdir /data/ssh/empty 0600 root shell

prebuilt/common/etc/init/lineage-updates.rc

@@ -1,4 +1,4 @@
 on post-fs-data
     # Create an additional OTA package directory that unlike /data/ota_package
     # will not be touched by GmsCore.
-    mkdir /data/lineageos_updates 0770 system cache
+    mkdir /data/lineageos_updates 0770 system cache encryption=Require