Return no product structures if reaction recipe action fails somewhere.

Prior to this, the molecule C1=CCC=C1 attempted to use the
1,4_Cyclic_birad_scission family in the reverse direction to
find a reaction.  There was no check that FORM_BOND should raise
an InvalidActionError if there is an existing bond between the
two atoms.  Therefore we were producing a nonsensical reaction
between [CH]1C[CH]CC1 = C1=CCC=C1

It turns out that many reactions prevent things like this from
happening by using forbidden groups (see Birad_recombination),
but it might be better to return no product structures when we
see the recipe application fail, since it is difficult to
come up with all forbidden groups beforehand.