Mask out SELinux intermediate files.

We don't want to install the SELinux intermediate files into device
image for now.

BUG=b:69139821
TEST=build_image

Change-Id: I3c25830a1b02aee9fb1dea19416be1003d056807
Reviewed-on: https://chromium-review.googlesource.com/1004079
Commit-Ready: Kenny Root <kroot@google.com>
Tested-by: Qijiang Fan <fqj@google.com>
Reviewed-by: Hidehiko Abe <hidehiko@chromium.org>
Reviewed-by: Kenny Root <kroot@google.com>
diff --git a/common.sh b/common.sh
index 860a431..feea2ab 100644
--- a/common.sh
+++ b/common.sh
@@ -443,6 +443,7 @@
   */.keep*
   /etc/init.d
   /etc/runlevels
+  /etc/selinux/intermediates
   /firmware
   /lib/modules/*/vdso
   /lib/rc