Dropped dmtcp

DMTCP has been introduced into our software as part of the R&D activity to evaluate the benefits of using the checkpoint-restart technique in Athena. Our study has showed that the benefits are rather questionable while, on the other hand, the usage of checkpoint-restart in production would bring in fairly non-trivial operational problems.

At the same time the presence of DMTCP in externals has become an obstacle for building our software stack on the platforms like PowerPC and MacOS.