[BUGFIX] Create symlinks to TYPO3 source as expected by the install tool

The new install tool in TYPO3 CMS 6.2 asked for a special symlink structure: http://d.pr/i/Fx5X
[TASK] Unlink symlinks to TYPO3 CMS source if already exist

This will ensure that `vagrant provision` will not result in errors because of already existing symlinks. Using `vagrant provision` can be handy while testing changes to the chef receipes.

Does this make sense?

I guess my suggested commands have quite some potential for improvements. Please feel free to change them if necessary. Thx.
Merge pull request #7 from mostwanted1976/patch-6

[BUGFIX] Create symlinks to TYPO3 source as expected by the install tool