biology/clustalw: Fix license, take maintainership
Approved by jrm (mentor) or wen (mentor)
Differential to be added to commit message

I'm stumped as to how this port got marked RESTRICTED. The license is LGPL:

http://www.clustal.org/clustal2/

Maybe the license was changed at some point?

portlint -AC: looks fine
Passed poudriere on {10.4,11.1}-{amd64,i386}
Tested in production