(ITS#5969) Update consumers csn when providers change

[rein@OpenLDAP.org]

Full_Name: Rein Tollevik
Version: cvs head
OS: irrelevant
URL: 
Submission from: (NULL) (84.215.36.97)
Submitted by: rein


The fix to ITS#5709 in syncprov.c rev 1.250 changed it to only update the
consumer csn when the queued csn is the greatest.  It should be updated whenever
syncprov updates its own csn, as the queued csn may be an older csn with a
different sid received from a remote syncrepl provider.

A fix is coming.  I haven't managed to get the test054 from ITS#5709 to fail
with this patch, while it failed almost immediately without the 1.250 fix.

Rein Tollevik
Basefarm AS