Item13079: Bootstrap doesn't gain admin rights.

If the user has a valid Foswiki session cookie, and the
working/tmp/cgisess_ file exists, then the bootstrap process fails to
set admin user, and runs as the current (stale) session user.

When loading the user from the session cookie, detect that we are in
bootstrap mode, and upgrade the session to admin.

core/lib/Foswiki/LoginManager.pm

@@ -371,6 +371,17 @@ sub loadSession {
             _trace( $this, "AUTHUSER from session is $sessionUser" )
               if defined $sessionUser;
 
+    # If we are bootstrapping, and the defaultUser from Foswiki.pm is admin
+    # Then override the session user to become admin.   This gets around a stale
+    # browser cookie from blocking the bootstrap admin login.
+
+            $authUser = $defaultUser
+              if ( $Foswiki::cfg{isBOOTSTRAPPING}
+                && $defaultUser eq 'admin' );
+
+            _trace( $this, "AUTHUSER after BOOTSTRAP check is $authUser" )
+              if defined $authUser;
+
             # An admin user stored in the session can override the webserver
             # user; handy for sudo