Allow vold to deleteAllKeys in Keystore

Add deleteAllKeys to IKeystoreMaintenance and allow vold to call it.
Allow vold to read the property
`ro.crypto.metadata_init_delete_all_keys.enabled`

Bug: 187105270
Test: booted twice on Cuttlefish
Change-Id: I2fb0e94db9d35c1f19ca7acb2f541cfb13c23524
diff --git a/private/property_contexts b/private/property_contexts
index 5475cbd..6d1bb6a 100644
--- a/private/property_contexts
+++ b/private/property_contexts
@@ -505,6 +505,7 @@
 ro.crypto.dm_default_key.options_format.version u:object_r:vold_config_prop:s0 exact int
 ro.crypto.fde_algorithm                         u:object_r:vold_config_prop:s0 exact string
 ro.crypto.fde_sector_size                       u:object_r:vold_config_prop:s0 exact int
+ro.crypto.metadata_init_delete_all_keys.enabled u:object_r:vold_config_prop:s0 exact bool
 ro.crypto.scrypt_params                         u:object_r:vold_config_prop:s0 exact string
 ro.crypto.set_dun                               u:object_r:vold_config_prop:s0 exact bool
 ro.crypto.volume.contents_mode                  u:object_r:vold_config_prop:s0 exact string