Allow init to relabel metadata block device.

In order to boot into GSI, we need init's second-stage block-device
machinery to relable metadata. This will allow it to format / mount
the block device later

Bug: 121209697
Test: device boots

Change-Id: I4e63151767345976b5667df74530cd69fffcfa89
Signed-off-by: Sandeep Patil <sspatil@google.com>
diff --git a/public/init.te b/public/init.te
index 59d500d..10a0c68 100644
--- a/public/init.te
+++ b/public/init.te
@@ -40,6 +40,7 @@
 # restorecon for early mount device symlinks
 allow init tmpfs:lnk_file { getattr read relabelfrom };
 allow init {
+  metadata_block_device
   misc_block_device
   recovery_block_device
   system_block_device