Use alias rule always

- I tested using the new RewriteCond and RewriteRule that were in the comments
  on my previous commit against a non-aliased host - and they work perfectly in
  that environment. As such, this is actually a better solution, as it will work
  in all cases.
- Documented the reasons for the rule in the file.
Merge pull request #153 from weierophinney/hotfix/htaccess-paas

Use alias rule always