Try and prevent problems from resolving AAAA

From resolv.conf(5):

    single-request-reopen (since glibc 2.9)
        The resolver uses the same socket for the A and AAAA
        requests. Some hardware mistakenly sends back only one
        reply. When that happens the client system will sit and wait
        for the second reply. Turning this option on changes this
        behavior so that if two requests from the same port are not
        handled correctly it will close the socket and open a new
        one before sending the second request.

GH-9
Harmless line that causes an error
Warn user of the wait during the install