Fix some rescue calls that do not specifiy error type. The problem I noticed was in style, several instances of `rescue` clauses that do not specify an exception type. This is noted in in the Ruby Style Guide as [Avoid rescuing the Exception class](https://github.com/bbatsov/ruby-style-guide#no-blind-rescues). My diagnosis was that at least some of those are leftover style. They are noted in `.rubocop_todo.yml`. To make sure, I asked on Slack. My fix is to make as many of them more specific, specifying at least `StandardError`, and trying to be more specific. No other ways of addressing this came to mind. I'd be happy to consider. (cherry picked from commit ff6b8712a0337305ba9617e35545b9e8f8cd4a53)