Remove simplecov gem on 1.8

Deprecation note indicates it will be removing even
no-op support for 1.8, so clarify now that it won’t
even be installed on those builds.

Gemfile

@@ -2,7 +2,7 @@ require File.expand_path('on_what', File.dirname(__FILE__))
 source 'https://rubygems.org'
 
 # Travis-only dependencies go here
-if on_travis?
+if on_travis? && !on_1_8?
   group :test do
     gem 'codecov', :require => false
   end

spec/spec_helper.rb

@@ -1,23 +1,26 @@
 require File.expand_path('on_what', File.dirname(File.dirname(__FILE__)))
 
-begin
-  require 'simplecov'
-  SimpleCov.start do
-    add_filter '/spec/'    # exclude test code
-    add_filter '/vendor/'  # exclude gems which are vendored on Travis CI
-  end
+# Code coverage (via SimpleCov) on Ruby 1.9+
+unless on_1_8?
+  begin
+    require 'simplecov'
+    SimpleCov.start do
+      add_filter '/spec/'    # exclude test code
+      add_filter '/vendor/'  # exclude gems which are vendored on Travis CI
+    end
 
-  # On CI, for Ruby 1.9+, we publish simplecov results to codecov.io
-  if on_travis? && !on_1_8?
-    require 'codecov'
-    SimpleCov.formatter = SimpleCov::Formatter::Codecov
-  end
+    # On CI we publish simplecov results to codecov.io
+    if on_travis?
+      require 'codecov'
+      SimpleCov.formatter = SimpleCov::Formatter::Codecov
+    end
 
-  # Due to circular dependency (simplecov depends on docile), remove and require again below
-  Object.send(:remove_const, :Docile)
-  $LOADED_FEATURES.reject! { |f| f =~ /\/docile\// }
-rescue LoadError
-  warn 'warning: simplecov or codecov gems not found; skipping coverage'
+    # Due to circular dependency (simplecov depends on docile), remove docile and require again below
+    Object.send(:remove_const, :Docile)
+    $LOADED_FEATURES.reject! { |f| f =~ /\/docile\// }
+  rescue LoadError
+    warn 'warning: simplecov or codecov gems not found; skipping coverage'
+  end
 end
 
 lib_dir = File.join(File.dirname(File.dirname(__FILE__)), 'lib')