This commit moves the backing files to /dev/shm to avoid limitations
that may be set on /tmp. The files are registered with pmix to ensure
they are cleaned up after an erroneous exit.
Signed-off-by: Nathan Hjelm <hjelmn@lanl.gov>
(cherry picked from commit 48101278160672317ade352365592f56ef3b8977)
47fd2313ab