mod_rewrite:Fix query string handling for proxied URLs.

PR:	14518
Obtained from:
Submitted by:	michael teitler <michael.teitler cetelem.fr>, Jan Kratochvil <rcpt-dev.AT.httpd.apache.org jankratochvil.net>
Reviewed by:	nd, jerenkrantz, minfrin


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/APACHE_2_0_BRANCH@105433 13f79535-47bb-0310-9956-ffa450edef68