Thread: pgsql: Fix overly-strict sanity check in BeginInternalSubTransaction

Log Message:
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Fix overly-strict sanity check in BeginInternalSubTransaction that made it
fail when used in a deferred trigger.  Bug goes back to 8.0; no doubt the
reason it hadn't been noticed is that we've been discouraging use of
user-defined constraint triggers.  Per report from Frank van Vugt.

Tags:
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REL8_0_STABLE

Modified Files:
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    pgsql/src/backend/access/transam:
        xact.c (r1.195.4.2 -> r1.195.4.3)

(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/access/transam/xact.c.diff?r1=1.195.4.2&r2=1.195.4.3)