figure it out at runtime (really meaning: we'll still default to "0"
unless something explicitly overrides to 1, such as the openib BTL).
This way, ompi_info doesn't confusingly report mpi_leave_pinned==0 for
mpi_leave_pinned, but we end up running with mpi_leave_pinned==1.
Fixes trac:1502.
This commit was SVN r19571.
The following Trac tickets were found above:
Ticket 1502 --> https://svn.open-mpi.org/trac/ompi/ticket/1502