suite-sparse: Fix conflicting openblas dependencies

Fixes breakage with numpy --with-openblas because of conflicting
dependencies: numpy asks for homebrew/science/openblas while suite-sparse
just asked for openblas, and homebrew did not realize they were the same
thing. This seems to be a recurring issue that was causing a lot of problems.

Closes #767. Fixes Homebrew/homebrew#27752.