Use phpstan-working-dir instead of (phpstan-get-working-dir)

The function is also called in phpstan-get-config-file, so it just
refers to the phpstan-working-dir variable.

Author: zonuexe

flycheck-phpstan.el

@@ -46,7 +46,7 @@
 
 (defun flycheck-phpstan--enabled-and-set-variable ()
   "Return path to phpstan configure file, and set buffer execute in side effect."
-  (let ((enabled (or (phpstan-get-working-dir) (phpstan-get-config-file))))
+  (let ((enabled (or phpstan-working-dir (phpstan-get-config-file))))
     (prog1 enabled
       (when (and phpstan-flycheck-auto-set-executable
                  (not (and (boundp 'flycheck-phpstan-executable)