Don't show full backtrace for rspec failures

This was making me sad, because I had to scroll past all the lines that implement the rspec example groups and matchers... none of which is at all interesting.

@jrafanie added the option so we don't miss out on lines from our customized rails.

So instead, I'll just remove any filter that would affect `ActiveRecord::Base.connection`, as a simple proxy for "any of rails".
It's `\d*`... I assume for `lib32`/`lib64` type stuff? Note that this is a `delete`: that's what the rspec built-in regex looks like. When I add it again below, I'm just trying to minimize the differences between mine and the original, to it's clear what I've changed.

(Though I have just noticed I managed to let `lib/` and `vmdb/` get out of sync. I'll fix that.)