Fix issues with FAILOVER
In particular it is possible when doing a multi-node failover
with a cascaded node for the result after the failover to
have nodes with a self subscription, a row in sl_subscribe
with the provider and receiver equal.

In fixing that issue we also discovered that slon was not
reloading the set origin's into memory following a FAILOVER
command.  This could mean that we were processing SYNC events
from a node which without realizing that node now is the origin
for a set.

Branch
------
master

Details
-------
https://git.postgresql.org/gitweb?p=slony1-engine.git;a=commitdiff;h=0974d0ca93eff1ed819beffa13370f1aff81e047

Modified Files
--------------
src/backend/slony1_funcs.sql | 17 +++++++++++++---
src/slon/remote_worker.c     | 15 +++++++++++++-
src/slon/runtime_config.c    | 48 ++++++++++++++++++++++++++++++++++++++++++++
src/slon/slon.h              |  1 +
4 files changed, 77 insertions(+), 4 deletions(-)