Fixes for uselist=True with m2o relationships

Fixes for uselist=True with m2o relationships

Fixed bug where a many-to-one relationship that specified ``uselist=True``
would fail to update correctly during a primary key change where a related
column needs to change.

Fixed bug where the detection for many-to-one or one-to-one use with a
"dynamic" relationship, which is an invalid configuration, would fail to
raise if the relationship were configured with ``uselist=True``.  The
current fix is that it warns, instead of raises, as this would otherwise be
backwards incompatible, however in a future release it will be a raise.

Fixes: #4772
Change-Id: Ibd5d2f7329ff245c88118e2533fc8ef42a09fef3