Fix a config tree problem.

The following configuration file demonstrates the problem:

<IfModule mod_rewrite.c>
RewriteEngine on
RewriteMap    quux-map       prg:/tmp/apache-2.0/map.quux.pl
RewriteRule   ^/~quux/(.*)$  /~quux/${quux-map:$1}
</IfModule>

After this config file is parsed, the only statement in the config
tree is the last statement in the IfModule container ("RewriteRule blah
blah").

The problem is that when ap_build_config_sub() handles this type of
construct, it moves *current to the end of the list before returning.
If this construct were the first thing in the file, the caller would
set conftree to *current, not realizing that there were list elements
before *current.  The caller doesn't have addressability to those list
elements.

With this change, ap_build_config_sub() sets *conftree before
walking *current to the end of the list.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@85993 13f79535-47bb-0310-9956-ffa450edef68