Remove unused `e` from `rescue Interrupt`.

Library/Homebrew/brew.rb

@@ -123,7 +123,7 @@ rescue SystemExit => e
   onoe "Kernel.exit" if ARGV.verbose? && !e.success?
   $stderr.puts e.backtrace if ARGV.debug?
   raise
-rescue Interrupt => e
+rescue Interrupt
   $stderr.puts # seemingly a newline is typical
   exit 130
 rescue BuildError => e