Fix some more warnings

Author: jonleighton

lib/spring/test/application.rb

@@ -121,7 +121,7 @@ def run(command, opts = {})
         @times << (Time.now - start_time) if @times
 
         output.merge(status: status, command: command)
-      rescue Timeout::Error => e
+      rescue Timeout::Error
         raise Timeout::Error, "While running command:\n\n#{dump_streams(command, read_streams)}"
       end
 

lib/spring/test/application_generator.rb

@@ -8,6 +8,7 @@ def initialize(version_constraint)
         @version            = RailsVersion.new(version_constraint.split(' ').last)
         @application        = Application.new(root)
         @bundled            = false
+        @installed          = false
       end
 
       def test_root

lib/spring/watcher/polling.rb

@@ -1,5 +1,3 @@
-require "spring/watcher"
-
 module Spring
   module Watcher
     class Polling < Abstract

test/unit/client/version_test.rb

@@ -5,7 +5,7 @@ class VersionTest < ActiveSupport::TestCase
   test "outputs current version number" do
     version = Spring::Client::Version.new 'version'
 
-    out, err = capture_io do
+    out, _ = capture_io do
       version.call
     end