The existing filtered UAs seem to catch the bulk of the traffic but
there are a few common ones that are still sneaking through. Add four
new rules for these cases.
All three are MSIE variants from version 6 to 9. All old enough that we
should be able to do this safely without impacting real users.
Change-Id: I8ae59f38de8b30bd06e1643ddbccf81ea32858aa
ebc2fa976c