Don't force WP to load the 'members' page when BP_ENABLE_ROOT_PROFILES

Forcing 'members' into the $wp_query query_args forces WP to load the Members
page as the currently queried object. This, in turn, causes problems with the
(somewhat obfuscated) way that BuddyPress manually manages 404 status when root
profiles are enabled. As a result, URLs like example.com/boone/foo (where 'foo'
is a nonexistent component) loaded the raw Members WP page, rather than 404ing
as BP has such a request do under normal circumstances.

We correct the problem by refraining from forcing $wp_query to load Members.

Fixes #5149

git-svn-id: https://buddypress.svn.wordpress.org/trunk@7581 cdf35c40-ae34-48e0-9cc9-0c9da1808c22