Fix typo: "an helm" -> "a helm"
Merge pull request #425 from cmpitg/patch-2

Fix typo: "an helm" -> "a helm"
Merge branch 'master' of github.com:emacs-helm/helm
* helm-files.el (helm-substitute-in-filename, helm-ff-auto-expand-to-home-or-root): Issue #424 attempt to fix regexp for unc paths on Windows.