Don't close STDOUT when calling the CA fetch_roots function
cm_subproc_mark_most_cloexec() now closes all open file
descriptors except for up to three requested for stdin, stdout
and stderr. Before the optimization those three were always
left open.
This was causing errors in the IPA helper ipa-server-guard
because it tries to display the contents of stderr which was
always being closed, causing ipa-server-guard to blow up.