make LICENSE more like choosealicense.com/licenses/bsd-3-clause/
make LICENSE more like choosealicense.com/licenses/bsd-3-clause/

see https://github.com/benbalter/licensee/issues/27

This commit should result in the GitHub license API being able to
correctly detect the license of this repository.

tianon/dh-make-golang,anthonyfok/dh-make-golang,paultag/dh-make-golang,paultag/dh-make-golang,tianon/dh-make-golang,Debian/dh-make-golang,aviau/dh-make-golang,aviau/dh-make-golang,anthonyfok/dh-make-golang,Debian/dh-make-golang