Log Message:
math/py-numpy: updated system_info patch to upstreamed version, use cblas

The patch to system_info.py got upstreamed in a modified form which is
now backported here. On updating to 1.21, it shall be dropped.

In the process of upstreaming the patch, I learned that numpy really
needs to use cblas for proper acceleration, so it does that now and
gets a PKGREVISION bump because of that.