Update the ssh/config filters in enter_chroot.sh
Update the ssh/config filters in enter_chroot.sh

The current instructions for golo access include additions to the
~/.ssh/config file that are specific to Google distros of ssh.  The
filtering mechanism in enter_chroot needed an update to include
these new options to filter out.

BUG=chromium-os:23322
TEST=With a golo-configured .ssh/config, enter chroot and test ssh:
> cros_sdk
> git remote update
Fetching ...
...

Change-Id: Ida9fcdff37ff0eb24c811ad789f82136dca7252f
Reviewed-on: https://gerrit.chromium.org/gerrit/12037
Tested-by: Matt Tennant <46e612415b446ccde19638e4035892001c237942@chromium.org>
Reviewed-by: David James <f231dc574bbeb62604660cbc162d1b8642a0a3af@chromium.org>
Reviewed-by: Zdenek Behan <483cf2a9a4e071d4fd973db6a5a78c40f490667c@chromium.org>
Commit-Ready: Matt Tennant <46e612415b446ccde19638e4035892001c237942@chromium.org>

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