rcbops/chef-cookbooks#751: not using 'wget' anymore to get remote files

- useful for boxes without wget installed
rcbops/chef-cookbooks#751: fixed issue when path attribute was changed

- when attribute node['collectd']['collectd_web']['path'] was changed
  between two Chef runs, the tarball wasn't extracted into the new path
Merge pull request #31 from darxriggs/wget-replacement

rcbops/chef-cookbooks#751: not using 'wget' anymore to get remote files