Fixed Downloading of magento tools by adding -L to curl command

The Magento-toolbox recipes failed to download some ressources from raw.github.com e.g.
https://raw.github.com/netz98/n98-magerun/master/n98-magerun.phar
By adding the -L option to the curl command, we make sure to follow redirects and fix the following error(s)

## Vagrant log:
================================================================================
Error executing action `run` on resource 'bash[download_n98-magerun]'
================================================================================

Mixlib::ShellOut::ShellCommandFailed
------------------------------------
Expected process to exit with [0], but received '1'
---- Begin output of "bash"  "/tmp/chef-script20140619-1850-kcrjkx-0" ----
STDOUT:
STDERR: % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0
chmod: cannot access `./n98-magerun.phar': No such file or directory
---- End output of "bash"  "/tmp/chef-script20140619-1850-kcrjkx-