Fixed bug whereby joining a select() of a table "A" with multiple

Fixed bug whereby joining a select() of a table "A" with multiple
foreign key paths to a table "B", to that table "B", would fail
to produce the "ambiguous join condition" error that would be
reported if you join table "A" directly to "B"; it would instead
produce a join condition with multiple criteria.
[ticket:2738]

Conflicts:
	doc/build/changelog/changelog_09.rst