Keep units from URL used for logout url building, when adding "logout" parameter to it

In INP-1162 task we've added a way to add "?logout=1" parameter into url of a page, where user is redirected after logout. It is trivial task to do for a regular url, but not so trivial for mod-rewrite one. To do it we need to:

1. disassemble url
2. add parameters to it
3. assemble url back again

This change however resulted in one side effect, that units, that were used to build original url are discarded during an assembly process.