Revert "Add a new environment variable PMI2_CONNECT_TO_SERVER. If set in the MPI"

This reverts commit 084787c0d8f266c7ff6b9ab1e2ce1e9a46065a2f.

Conflicts:

	NEWS
	contribs/pmi2/pmi2_api.c
	src/plugins/mpi/pmi2/mpi_pmi2.c