Slightly rearranged the treatment of transaction ids so as to avoid

Slightly rearranged the treatment of transaction ids so as to avoid
repeated calls to getXactId().  Also: when committing or rolling back,
return the transaction id from getXactId() instead of referencing the
session_id of the application session.

In dispatchCRUDMethod: Added comments.  Renamed meta to method_meta
to distinguish it from class metadata.  Avoid unnecessary lookups of
the class metadata.  Rearrange things a bit for clarity.

M    Open-ILS/src/c-apps/oils_cstore.c

git-svn-id: svn://svn.open-ils.org/ILS/trunk@15689 dcc99617-32d9-48b4-a31d-7c20da2025e4