travis: Include the python version in homebrew deps string.
travis: Include the python version in homebrew deps string.

dagophil/vigra,dstoe/vigra,funkey/vigra,dstoe/vigra,funkey/vigra,funkey/vigra,dagophil/vigra,dagophil/vigra,dstoe/vigra,dagophil/vigra,funkey/vigra,dagophil/vigra,dstoe/vigra,dagophil/vigra,funkey/vigra,funkey/vigra,dstoe/vigra,dstoe/vigra,dagophil/vigra,dstoe/vigra,funkey/vigra