Bug 285 fix move set race condition.

During a move set it is possible on subscriber node, that isn't the
old or new origin, for remoteWorkerThread_$oldorigin to start
processing a SYNC event before the ACCEPT_SET is processed
by the remoteWorkerThread_$neworigin.  If the ACCEPT_SET
transaction then commits before the update sl_setsync
query is executed by the remoteWorkertThread_$oldorigin
the update will update a row for the new origin when
it intends to update the old origin.  This messes up
sl_setsync.

This change will add a condition to the WHERE clause so
a remoteWorkerThread won't UPDATE rows for a different
origin

Branch
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REL_2_1_STABLE

Details
-------
http://git.postgresql.org/gitweb?p=slony1-engine.git;a=commitdiff;h=16905a341cf6a90dc8fd24aa8e6650cfec6b5e61

Modified Files
--------------
RELEASE                  |    3 +++
src/slon/remote_worker.c |    5 ++---
2 files changed, 5 insertions(+), 3 deletions(-)