init.rc: mkdir /data/anr 0775 system system

Ensure that /data/anr always exists. This allows us to eliminate
some code in system_server and dumpstate. In addition, this change
solves a common problem where people would create the directory
manually but fail to set the SELinux label, which would cause
subsequent failures when they used the directory for ANRs.

Bug: 22385254
Change-Id: I29eb3deb21a0504aed07570fee3c2f87e41f53a0
diff --git a/rootdir/init.rc b/rootdir/init.rc
index b7a593f..f5febde 100644
--- a/rootdir/init.rc
+++ b/rootdir/init.rc
@@ -292,6 +292,7 @@
     mkdir /data/mediadrm 0770 mediadrm mediadrm
 
     mkdir /data/adb 0700 root root
+    mkdir /data/anr 0775 system system
 
     # symlink to bugreport storage location
     symlink /data/data/com.android.shell/files/bugreports /data/bugreports