Remove Appraisal for handcrafted Gemfiles, determine Nokogiri dependency at runtime for Rails versions that can run older Rubies

f067b34 is an incorrect solution, Ruby 2.4.1 and Rails 4.2 is a valid combo and to have no deprecation warnings that combination requires Nokogiri >= 1.7.

Author: Bart de Water

Appraisals

@@ -5,6 +5,5 @@ source "https://rubygems.org"
 gem "actionpack", "~> 4.0.0"
 gem "activerecord", "~> 4.0.0"
 gem "railties", "~> 4.0.0"
-gem "nokogiri", "~> 1.6.0"
 
 gemspec :path => "../"

gemfiles/rails_4.0.gemfile

@@ -5,6 +5,5 @@ source "https://rubygems.org"
 gem "actionpack", "~> 4.1.0"
 gem "activerecord", "~> 4.1.0"
 gem "railties", "~> 4.1.0"
-gem "nokogiri", "~> 1.6.0"
 
 gemspec :path => "../"

gemfiles/rails_4.1.gemfile

@@ -5,6 +5,5 @@ source "https://rubygems.org"
 gem "actionpack", "~> 4.2.0"
 gem "activerecord", "~> 4.2.0"
 gem "railties", "~> 4.2.0"
-gem "nokogiri", "~> 1.6.0"
 
 gemspec :path => "../"

gemfiles/rails_4.2.gemfile

@@ -5,6 +5,5 @@ source "https://rubygems.org"
 gem "actionpack", "~> 5.0.0"
 gem "activerecord", "~> 5.0.0"
 gem "railties", "~> 5.0.0"
-gem "nokogiri", "~> 1.7.0"
 
 gemspec :path => "../"

gemfiles/rails_5.0.gemfile

@@ -5,6 +5,5 @@ source "https://rubygems.org"
 gem "actionpack", "~> 5.1.0"
 gem "activerecord", "~> 5.1.0"
 gem "railties", "~> 5.1.0"
-gem "nokogiri", "~> 1.7.0"
 
 gemspec :path => "../"