If you autogen.pl --without-prrte, we wouldn't configure or build PRRTE
support. However, configuring with --disable-internal-rte wasn't working
as it was being ignored. This led to some false errors when compiling
with an earlier PMIx v2.2 release.
That said, there were a couple of places that needed protection against
PMIx v2.2.
Signed-off-by: Ralph Castain <rhc@pmix.org>