Reduce explicit branches in dependency expansion
Test default formula requirements against correct dependent
Remove unreachable branch

Requirements meeting this condition are skipped by the first branch
on the caller side:

https://github.com/Homebrew/homebrew/blob/6c54de812f00658404501719d315202a5551cc1b/Library/Homebrew/formula_installer.rb
finch 2.10.10

Not sure why this wasn’t bumped when Pidgin was the other day, so
here’s a bump. Also, style updates, and a conflicts_with “pidgin”
because they are exactly the same piece of software, just one with a
GUI and one without, but trying to install both causes brew link to
have a small freakout.
finch: add 2.10.10 bottle.