Attempt to get the build running on Ruby 2.2

It appears we're getting a newer version of this multipart-post
dependency, which doesn't work well with Ruby 2.2 by using
`Object.deprecate_constant`, resulting in the following error:

    .../multipart-post-2.2.0/lib/multipart/post/parts.rb:152:in `<top (required)>':
    undefined method `deprecate_constant' for Object:Class (NoMethodError)

Hopefully by locking on a previous version we can just get the build
back to green for now.

gemfiles/Gemfile-rails-4-1

@@ -38,3 +38,9 @@ end
 group :mongoid do
   gem "mongoid", "~> 4.0"
 end
+
+if RUBY_VERSION < "2.3.0"
+  # We're getting version 2.2.0 which doesn't play nice with Ruby 2.2, using
+  # `Object.deprecate_constant` which isn't available.
+  gem "multipart-post", "2.1.1"
+end

gemfiles/Gemfile-rails-4-2

@@ -37,3 +37,9 @@ end
 group :mongoid do
   gem "mongoid", "~> 4.0"
 end
+
+if RUBY_VERSION < "2.3.0"
+  # We're getting version 2.2.0 which doesn't play nice with Ruby 2.2, using
+  # `Object.deprecate_constant` which isn't available.
+  gem "multipart-post", "2.1.1"
+end

gemfiles/Gemfile-rails-5-0

@@ -30,3 +30,9 @@ end
 # group :mongoid do
 #   gem "mongoid", "~> 4.0.0"
 # end
+
+if RUBY_VERSION < "2.3.0"
+  # We're getting version 2.2.0 which doesn't play nice with Ruby 2.2, using
+  # `Object.deprecate_constant` which isn't available.
+  gem "multipart-post", "2.1.1"
+end

gemfiles/Gemfile-rails-5-1

@@ -23,3 +23,9 @@ end
 platforms :ruby do
   gem "sqlite3", "~> 1.3.6"
 end
+
+if RUBY_VERSION < "2.3.0"
+  # We're getting version 2.2.0 which doesn't play nice with Ruby 2.2, using
+  # `Object.deprecate_constant` which isn't available.
+  gem "multipart-post", "2.1.1"
+end