init: Always create and restorecon /dev/dm-user.

Dynamically creating /dev/dm-user makes it difficult to set an inotify
watch for child devices to appear. It requires having an additional
watch on /dev, and more complicated sepolicy as a result.

Bug: 168554689
Test: full OTA with VABC enabled
Change-Id: I0cdef3d5a953a372446ff4e539a25a7b5314500d
diff --git a/init/selinux.cpp b/init/selinux.cpp
index 5a0255a..f03ca6b 100644
--- a/init/selinux.cpp
+++ b/init/selinux.cpp
@@ -534,6 +534,7 @@
     selinux_android_restorecon("/dev/__properties__", 0);
 
     selinux_android_restorecon("/dev/block", SELINUX_ANDROID_RESTORECON_RECURSE);
+    selinux_android_restorecon("/dev/dm-user", SELINUX_ANDROID_RESTORECON_RECURSE);
     selinux_android_restorecon("/dev/device-mapper", 0);
 
     selinux_android_restorecon("/apex", 0);