Various cleanups in transport_session.c:

Various cleanups in transport_session.c:

1. In init_transport(): guard against a NULL server parameter.

2. In session_free(): if the session is still open, disconnect it.

3. In session_connect():  if we open a socket but are unable to connect to Jabber, close the
socket and set the sock_id member to zero.  If the socket is already open, return an error,
instead of reusing the existing socket (and trying to overlay any open Jabber session).

4. In session_connect(): guard against an invalid auth_type.

5. In session_connect(): corrected some errors in the way we calculate buffer sizes,

6. In session_disconnect(): send a disconnect message only if the socket is still open.

7. Tidied up white space and comments in various places.

8. Added doxygen-style comments to document some of the functions.

M    src/libopensrf/transport_session.c

git-svn-id: svn://svn.open-ils.org/OpenSRF/trunk@1822 9efc2488-bf62-4759-914b-345cdb29e865