Fixing lapack formula

The old formula resulted in the following:
<pre>
==> make PREFIX=/usr/local/Cellar/lapack/3.4.0 install
make PREFIX=/usr/local/Cellar/lapack/3.4.0 install
make: Nothing to be done for `install'.
</pre>

and no libraries were built or installed.  This is fixed now.

On a related note, there is no dupe formula for blas.  Should this formula make and install blas as well (the lapack tarball contains blas source), or should there be a separate formula?