pylith generates an MPI error if run offline

[baagaard-usgs]

Describe the bug

In using the PyLith binary offline, the following error often occurs

Abort(941216911): Fatal error in internal_Init: Other MPI error, error stack:
internal_Init(66)........: MPI_Init(argc=0x30e02abe8, argv=0x30e02abe0) failed
MPII_Init_thread(234)....: 
MPID_Init(513)...........: 
MPIDI_OFI_init_local(580): OFI fi_fabric failed (ofi_init.c:580:MPIDI_OFI_init_local:Invalid argument)

This appears to be related to the hostname.

[baagaard-usgs]

The workaround is to use sockets for MPI communication by setting the environment variable IF_PROVIDER to sockets.

export FI_PROVIDER=sockets