Obviously his popularity will decline because it is likely that Russians are subjected to a large among of propaganda from their government. I fail to see why this is important on an international level. Bruce Willis is an actor and his popularity abroad really isn't important in a real sense.
Here in the US, the bailout of failing banks has been a controversial issue, with many citizens objecting to the idea that their tax dollars should save the failing institutions. This is due in part to ideas we hold about fairness and equality of opportunity for "the little guy". Russia is a different culture and a different country, and consequently the fallout from this bailout should not be nearly as severe.
The rumors of Bruce Willis' popularity taking a hit are being greatly exaggerated. He support of Trust Bank and the decision to go public might not have been the best idea, but it appears he hasn't had enough impact to really make a difference. People usually won't hold an opinion against a person if they don't agree and this appears to be the case with Bruce Willis.
Russian popular opinion is not directed negatively towards agents of the Russian economy such as the banks but towards foreign powers acting in opposition to Putin. However, even if there was animosity towards the bank, people wouldn't blame the celebrity face of the brand but the people who work there in other capacities.