Travis CI: MPI installation failure on Linux

[kose-y]

Installation of mpich and intel mpi fails on linux.

[kose-y]

Looks like this is happening somewhat randomly.

https://travis-ci.org/JuliaParallel/MPI.jl/builds/560302399?utm_source=github_status&utm_medium=notification

[simonbyrne]

This seems to have resolved itself recently.

[simonbyrne]

I spoke too soon:

[Traviss-Mac-80:86046] *** An error occurred in MPI_Barrier

[Traviss-Mac-80:86046] *** reported by process [2356281345,1]

[Traviss-Mac-80:86046] *** on communicator MPI_COMM_WORLD

[Traviss-Mac-80:86046] *** MPI_ERR_OTHER: known error not in list

[Traviss-Mac-80:86046] *** MPI_ERRORS_ARE_FATAL (processes in this communicator will now abort,

[Traviss-Mac-80:86046] ***    and potentially your MPI job)

It may be worth trying out a different CI provider. I've had good luck with Azure Pipelines recently.