General nits for this file:
* two space indentation instead of four
* please review your use of semicolons
* missing license header
* missing `"use strict";`
* use of `'` vs. `"` for string literals
* static references declared on top of the file should start capitalized, with a descriptive name, like `jsDAV_DAVACL_Backends_PostGre = require("...");`. It might seem long, java-ish, etc., but it certainly helps maintaining readability of the entire source base.