allow init to open kmsg_debug

The 'stdio_to_kmsg' option will print stdout and stderr to
kmsg_debug.  This requires init to be able to open kmsg_debug.

Test: services with stdio_to_kmsg can print to kmsg_debug
Change-Id: I63f0af8f079f7327c1224aa9e46f19d6549d875b
diff --git a/public/init.te b/public/init.te
index de6d4d4..3a59641 100644
--- a/public/init.te
+++ b/public/init.te
@@ -14,7 +14,7 @@
 allow init kmsg_device:chr_file { getattr write relabelto };
 # /dev/kmsg_debug
 userdebug_or_eng(`
-  allow init kmsg_debug_device:chr_file { write relabelto };
+  allow init kmsg_debug_device:chr_file { open write relabelto };
 ')
 # /dev/__properties__
 allow init properties_device:dir relabelto;