Pass -lLTO after gold-plugin.o.

We have to pass -lLTO after gold-plugin.o, otherwise it will
be ignored when --as-needed is used as well.  This is
backported from the upstream r162652.

------------------------------------------------------------
commit a16c2e34
Author: Rafael Espindola <rafael.espindola@gmail.com>
Date:   Mon Aug 27 03:03:07 2012 +0000

    Pass -lLTO after gold-plugin.o so that it gets used in
    systems that default --as-needed.  Patch by Felix Geyer.
    Fixes pr13262.

    git-svn-id:
    https://llvm.org/svn/llvm-project/llvm/trunk@162652
    91177308-0d3
------------------------------------------------------------

Change-Id: I3d90a9cb51aa64b036026b71ddf544aa8d7b3768