Lock rake to a version pre 11.0

Rake version 11.0 removed the `last_comment`
method which is used by `rspec 2.14.x` which we
use in this test app.

gemfiles/rails32.gemfile

@@ -1,6 +1,6 @@
 source 'https://rubygems.org'
 
-gem 'rake', '>= 0.9'
+gem 'rake', '>= 0.9', '< 11.0'
 gem 'rdoc', '>= 2.4.2'
 
 platforms :jruby do

gemfiles/rails40.gemfile

@@ -1,6 +1,6 @@
 source 'https://rubygems.org'
 
-gem 'rake', '>= 0.9'
+gem 'rake', '>= 0.9', '< 11.0'
 gem 'rdoc', '>= 2.4.2'
 
 platforms :jruby do

tests/test_app/Gemfile

@@ -1,6 +1,7 @@
 source 'https://rubygems.org'
 
 gem 'rails', '~> 3.2'
+gem 'rake', '< 11.0'
 
 gem 'impressionist', :path => '../../'