epicmtd: releasetools: Add selinux restorecon script.

After an update, /system is being left unlabeled.  However, /system/*
gets properly labeled so the init.d restorecon script is not executed.

Hack around that by adding restorecon.sh to the end of the updater-script.

Change-Id: I2ba1cd23def13a2566dc8998129aa0656689849d