Include metacpan mirrors in formulae using search.cpan.org.

A few weeks ago I had experienced issues installing a package which used search.cpan.org, which was unfortunatly down at that very moment. 

By that evening I found some extra time to troubleshoot the issue and I was able to rewrite the formula quickly to use metacpan.org. This allowed me to install without issue. I am providing this update as a request that these formulae which used search.cpan.org also include the mirror metacpan.org to improve reliability and prevent this issue in the future were there to be any unfortunate server outages at cpan.org for others.