Paul Hargrove pointed out that Stevens tells us that we should
FD_GETFL before FD_SETFL. And so we shall.
Make a new convenience function to do this (opal_fd_set_cloexec()),
just so that we don't have to litter this 2-step process throughout
the code.
Refs trac:4550
This commit was SVN r31513.
The following Trac tickets were found above:
Ticket 4550 --> https://svn.open-mpi.org/trac/ompi/ticket/4550