`lib/support/init.d/gitlab` was set as executable in the repo as of the
6.1 release so chmod is not needed after that. See
https://github.com/gitlabhq/gitlabhq/pull/7586/files#r16885445.
Update `curl` commands to follow redirects (see
http://curl.haxx.se/docs/manpage.html#-L). Current `curl` commands will
return unexpected results if the requested content has been moved and is
returning information about where it has been moved to. Including the
`-L` option tells `curl` to follow the redirect so the file can be
correctly acquired.