make htaccess deny in src and app work with apache 2.4
bug #621 make htaccess deny in src and app work with apache 2.4 (Tobion)

This PR was merged into the 2.3 branch.

Discussion
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make htaccess deny in src and app work with apache 2.4

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | |no
| Tests pass?   | yes
| Fixed tickets | #602
| License       | MIT

Based on findings in https://drupal.org/node/1599774
Made it work under both apache 2.2 and 2.4.

Commits
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38c2a50 make htaccess deny in src and app work with apache 2.4
Merge remote-tracking branch 'symfony/2.3'
Updated Vagrantfile