Grant sdcard_r to ril-daemon.

Bug: 6793799
Change-Id: Ife23c98c30d7b08479d75798c7075005bf281119

rootdir/init.rc

diff --git a/rootdir/init.rc b/rootdir/init.rc
index bb7e4ea..e1371df 100644
--- a/rootdir/init.rc
+++ b/rootdir/init.rc
@@ -392,7 +392,7 @@
     socket rild stream 660 root radio
     socket rild-debug stream 660 radio system
     user root
-    group radio cache inet misc audio sdcard_rw log
+    group radio cache inet misc audio sdcard_r sdcard_rw log
 
 service surfaceflinger /system/bin/surfaceflinger
     class main