Sepolicy changes for system_server to use libvintf

Test: Boot sailfish with shared system image
Bug: 36814984
Change-Id: I2937c20c3b6ca7bf4edab66a74742c48e76c7687
diff --git a/private/system_server.te b/private/system_server.te
index 925c82d..0e4ecda 100644
--- a/private/system_server.te
+++ b/private/system_server.te
@@ -86,6 +86,9 @@
 allow system_server self:netlink_socket create_socket_perms_no_ioctl;
 allow system_server self:netlink_generic_socket create_socket_perms_no_ioctl;
 
+# libvintf reads the kernel config to verify vendor interface compatibility.
+allow system_server config_gz:file { read open };
+
 # Use generic "sockets" where the address family is not known
 # to the kernel. The ioctl permission is specifically omitted here, but may
 # be added to device specific policy along with the ioctl commands to be