[Cbc] CbcMain1 returns bogus result when it cannot improve on setBestSolution

[Jack Vreeken]

That may be possible, but I'd rather not resort to writing/reading files as there may be multiple concurrent processes writing to the same folder. Note that CBCs current behavior probably still allows me to do what I need to do, if I just copy and store the .currentSolution() after calling .setBestSolution(). It just feels a bit weird to me that CbcMain1 would return with a totally different result than the optimal one in this particular case.