Do not block in query upcall

We cannot block in an upcall into the host, so do the right
thing and allow the host to callback asynchronously when
servicing a "resolve" request

Signed-off-by: Ralph Castain rhc@pmix.org
(cherry picked from commit ce3f5a4)

Further cleanup of "resolve" functions

If the host supports the "query" upcall interface, they
will return SUCCESS to mean that they are servicing the
request. It does not mean that they will understand the
key(s) being passed to them - in which case, they will
issue the callback with some status other than SUCCESS.

Should that happen, we still want the server to attempt
to resolve the request to the best of its ability. So
provide a mechanism by which the server gets a second
shot at providing the answer.

Signed-off-by: Ralph Castain rhc@pmix.org
(cherry picked from commit 76bd862)

Silence error output when running as singleton

When executed as a singleton, we automatically search
for available connections, just like a tool would do.
However, if they are not found, we should not emit an
error message if we were not specifically directed
to find one - e.g., a system-level server.

Also fix the query operation to return any partial
results it was able to find when operating as
a singleton.

Signed-off-by: Ralph Castain rhc@pmix.org
(cherry picked from commit 2a762ff)