Install: Allow an installation to go through with a custom user table with the username 'admin'.

This could be better, but this solves the regression caused by [25115].

fixes #27093, see #24078.

Built from https://develop.svn.wordpress.org/trunk@27822


git-svn-id: http://core.svn.wordpress.org/trunk@27656 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/install.php

@@ -102,6 +102,7 @@ function display_setup_form( $error = null ) {
 			<?php
 			if ( $user_table ) {
 				_e('User(s) already exists.');
+				echo '<input name="user_name" type="hidden" value="admin" />';
 			} else {
 				?><input name="user_name" type="text" id="user_login" size="25" value="<?php echo esc_attr( sanitize_user( $user_name, true ) ); ?>" />
 				<p><?php _e( 'Usernames can have only alphanumeric characters, spaces, underscores, hyphens, periods and the @ symbol.' ); ?></p>