openblas: 0.3.0 -> 0.3.1

Since the exposure of the version attribute done in
892a0e8f, the OpenBLAS build fails for
i686-linux:

https://nix-cache.s3.amazonaws.com/log/wi79zyfmwdpwx7bm29dzqh4vglx3x550-openblas-0.3.0.drv

According to @edolstra the build slaves of Hydra updated to a new
kernel, which seems to be the real cause for this issue. The latter is
already tracked upstream[1] and a fix[2] is already included in version
0.3.1.

This very update cases 4795 rebuilds across all architectures we
support, so it's still not significant enough to go through staging. In
addition the number of rebuilds doesn't include the amount of builds
that are currently failing.

My original idea was to add a patch just for fixing this on i686-linux
and do the real update via staging, but the amount of rebuilds still is
in an acceptable range IMO and @edolstra agreed on that on IRC.

[1]: https://github.com/xianyi/OpenBLAS/issues/1575
[2]: https://github.com/xianyi/OpenBLAS/pull/1583



Signed-off-by: aszlig <aszlig@nix.build>
Cc: @ttuegel