bug 321 - Stop reconnecting to providers

Event origins that are not set origins will have
multiple  li_origin/li_receiver pairs in sl_listen
we listen for events from these origins from multiple
sources.   This means a node such as node 2 might
receive an event from ev_origin=1 via event provider 1
then receive the next event with ev_origin=1 from
event provider 2.  Slon keeps connecting and
disconnecting from these providers.

Instead keep of dropping the connections to
event providers we keep them around unless
a reconfiguration has taken place.  This lets
us use the connection for the event_provider
we received the event from.

Branch
------
REL_2_2_STABLE

Details
-------
http://git.postgresql.org/gitweb?p=slony1-engine.git;a=commitdiff;h=8ad8ab9cb13ffc410aa43013722f3a48b18e4ea2

Modified Files
--------------
src/slon/remote_worker.c |   44 ++++++++++++++++++++++++++++++++++++++------
1 file changed, 38 insertions(+), 6 deletions(-)