This commit fixes a segfault in mtl-portals4 finalize(). The segfault
occurs if finalize() is called without any calls to add_procs(). This
commit resolves the segfault by skipping the flow control fini() call if
Portals4 was not initialized.
Signed-off-by: Todd Kordenbrock <thkgcode@gmail.com>
(cherry picked from commit e7b867c044f8b776b75f3c6d917745c06237743e)