Allow snapuserd interaction in recovery and fastbootd.

This is needed to support VABC merges on data wipes and via "fastboot
snapshot-update merge".

Bug: 168258606
Test: fastboot snapshot-update merge
      data wipe during VABC merge
Change-Id: I32770a2e74f2c2710e4964f65c42ae779c1a0b90
diff --git a/private/fastbootd.te b/private/fastbootd.te
index f0ba02c..98eb23c 100644
--- a/private/fastbootd.te
+++ b/private/fastbootd.te
@@ -28,6 +28,14 @@
   allow fastbootd port:tcp_socket name_bind;
   allow fastbootd self:tcp_socket { create_socket_perms_no_ioctl listen accept };
 
+  # Start snapuserd for merging VABC updates
+  set_prop(fastbootd, ctl_snapuserd_prop)
+
+  # Needed to communicate with snapuserd to complete merges.
+  allow fastbootd snapuserd_socket:sock_file write;
+  allow fastbootd snapuserd:unix_stream_socket connectto;
+  allow fastbootd dm_user_device:dir r_dir_perms;
+
   # Get fastbootd protocol property
   get_prop(fastbootd, fastbootd_protocol_prop)
 ')