LP#1350457: Pass caller's session to subrequests called via method_lookup

LP#1350457: Pass caller's session to subrequests called via method_lookup

In the process of looking up a method for an internal subrequest, we lose
session info. This is a problem when the subrequest makes a remote request,
because then the subrequest can't look up the proper locale, among other
things. The forthcoming branch passes the caller's session to the subrequest.

This patch also teaches OpenSRF object registration how to strip certain
object members -- in particular, the session -- so that introspection
continues to work.

Signed-off-by: Mike Rylander <mrylander@gmail.com>
Signed-off-by: Galen Charlton <gmc@esilibrary.com>