Get "make install" to work on Tru64.

Get "make install" to work on Tru64.

With Tru64, make picks up a bad status from the child shell process
when it evaluates the "`echo ($static) | grep 'mod_so'` (see below),
causing make to bail out.

But that grep should always fail when "make install" runs in
modules/extra and unless we have mod_so it will fail when "make
install" runs in modules/standard.

The work-around is to explicitly ignore the exit status from the
grep.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@86959 13f79535-47bb-0310-9956-ffa450edef68