Curl fails to download Drush

Adding the `-L` parameter fixes the issue

> -L: "If the server reports that the requested page has moved to a different location (indicated with a Location: header and a 3XX response code), this option will make curl redo the request on the new place."

```
diff --git a/lib/capdrupal.rb b/lib/capdrupal.rb
old mode 100644
new mode 100755
index 97f3382..9a54023
--- a/lib/capdrupal.rb
+++ b/lib/capdrupal.rb
@@ -183,7 +183,7 @@ Capistrano::Configuration.instance(:must_exist).load do
namespace :drush do
desc "Gets drush and installs it"
task :get, :roles => :app, :except => { :no_release => true } do
- run "#{try_sudo} cd #{shared_path} && curl -O -s http://ftp.drupal.org/files/projects/drush-7.x-5.8.tar.gz && tar -xf drush-7.x-5.8.tar.gz && rm drush-7.x-5.8.tar.gz"
+ run "#{try_sudo} cd #{shared_path} && curl -LO -s http://ftp.drupal.org/files/projects/drush-7.x-5.8.tar.gz && tar -xf drush-7.x-5.8.tar.gz && rm drush-7.x-5.8.tar.gz"
run "#{try_sudo} cd #{shared_path} && chmod u+x drush/drush"
end
```