Avoid unused variable warning when APR_HAVE_IPV6 == 0.
Avoid unused variable warning when APR_HAVE_IPV6 == 0.

* subversion/libsvn_ra_svn/client.c (make_connection): Wrap declaration of
    ipv6_supported in #if APR_HAVE_IPV6.


git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@853649 13f79535-47bb-0310-9956-ffa450edef68

wbond/subversion,YueLinHo/Subversion,YueLinHo/Subversion,wbond/subversion,wbond/subversion,wbond/subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,wbond/subversion,YueLinHo/Subversion,YueLinHo/Subversion,wbond/subversion,YueLinHo/Subversion,wbond/subversion