Remove reference to unused reload_paths option (#2322)

The option was removed in bedf235ff6.
However, it wasn't deleted from the params hash, so a nil value is
always being passed in.

middleman-cli/lib/middleman-cli/server.rb

@@ -45,7 +45,6 @@ module Middleman::Cli
       params = {
         debug: options['verbose'],
         instrumenting: options['instrument'],
-        reload_paths: options['reload_paths'],
         daemon: options['daemon']
       }