Revert openblas

[rodluger]

See rodluger/starry#255

[fbartolic]

@rodluger I'm getting the following error after this merge:

WARNING (theano.tensor.blas): We did not find a dynamic library in the library_dir of the library we use for blas. If you use ATLAS, make sure to compile it with dynamics library.

This slows everything down by at least an order of magnitude.

I tried explicitly pointing theano to the library by adding export THEANO_FLAGS=blas.ldflags="-L/usr/lib/ -lopenblas" to azure-pipelines.yml as suggested here but it didn't work. Did you have this problem before?

[rodluger]

Looks like you were getting this warning before the merge as well:
https://dev.azure.com/constan7in3/volcano/_build/results?buildId=53&view=logs&j=d0f5d444-fce9-5962-ba7d-d71684238647&t=381d5e61-fc54-5591-7254-12d08113255d&l=18

Looking at my starry builds, it seems that I've always had this warning on Azure, but it's never noticeably impacted performance for me.

So, it doesn't seem like this is the issue causing the slowdown...

[fbartolic]

Hmmm, there's definitely a noticeable slowdown compared to some previous builds. I might just give up on trying to build figures on azure again.

[dfm]

I don't understand why you're installing openblas anyways? MKL already implements everything you need and it should be better.