assertion botched on Open MPI

We also found a problem similar to the one described in #14
but with OpenMPI and a different error.
The error can be reproduced on two different clusters.

Cluster A:
```
malloc: unknown:0: assertion botched
free: called with unallocated block argument
Aborting...[A-c7-048-16:05963] *** Process received signal ***
[A-c7-048-16:05963] Signal: Aborted (6)
[A-c7-048-16:05963] Signal code: (-6)
```

Cluster B:
```
user@B0:~/Projects/mpibash/MPI-Bash/examples$ mpirun -n 8 ./testmpi
[B13:19987] *** Process received signal ***
malloc: unknown:0: assertion botched
```

Start by comparing the failure with issue #14 and reproducing it using `mpirun -n 8 ./testmpi` on an available Open MPI environment. No source file or test is named; done means identifying and resolving the allocation/assertion failure across the reported cluster scenarios.

Written by the indexing model from the issue text.