BUG-5507: ignore schema-related AutoAttach errors

When initialising OvsdbAutoAttachedRemovedCommand and
OvsdbAutoAttachUpdateCommand, schemas without support for autoattach
cause IllegalArgumentException to be thrown. This is in all likelihood
the only scenario which can lead to this, so for now ignore the
exceptions.

A proper fix would involve checking the schema as done in TyperUtils.
Once this is done these constructors will be updated to use that
instead of ignoring IllegalArgumentException.

Change-Id: Idd284ab8acdc0886ef11dae6ecfb410e487ca312
Signed-off-by: Stephen Kitt <skitt@redhat.com>