ThreadPool: log the generic exception more explicitly
ThreadPool: log the generic exception more explicitly

thumbor/thumbor,thumbor/thumbor,marcelometal/thumbor,thumbor/thumbor,scorphus/thumbor,okor/thumbor,okor/thumbor,kkopachev/thumbor,gi11es/thumbor,scorphus/thumbor,okor/thumbor,voxmedia/thumbor,scorphus/thumbor,thumbor/thumbor,marcelometal/thumbor,voxmedia/thumbor,voxmedia/thumbor,scorphus/thumbor,gi11es/thumbor,kkopachev/thumbor,kkopachev/thumbor,gi11es/thumbor,marcelometal/thumbor,kkopachev/thumbor