gnu: ruby-simplecov-html: Fix hash and disable tests.

* gnu/packages/ruby.scm (ruby-simplecov-html)[source]: Replace incorrect
  hash.
[arguments]: Disable tests.

gnu: Add ruby-net-ssh.

* gnu/packages/ruby.scm (ruby-net-ssh): New variable.

gnu: Add ruby-mocha.

* gnu/packages/ruby.scm (ruby-mocha): New variable.

gnu: Add ruby-redcarpet.

* gnu/packages/ruby.scm (ruby-redcarpet): New variable.

gnu: Add ruby-introspection.

* gnu/packages/ruby.scm (ruby-introspection): New variable.

gnu: Add ruby-instantiator.

* gnu/packages/ruby.scm (ruby-instantiator): New variable.

gnu: Add ruby-blankslate.

* gnu/packages/ruby.scm (ruby-blankslate): New variable.

gnu: Add ruby-metaclass.

* gnu/packages/ruby.scm (ruby-metaclass): New variable.

gnu: Add ruby-test-unit.

* gnu/packages/ruby.scm (ruby-test-unit): New variable.

gnu: Add ruby-packnga.

* gnu/packages/ruby.scm (ruby-packnga): New variable.

gnu: Add ruby-gettext.

* gnu/packages/ruby.scm (ruby-gettext): New variable.

gnu: Add ruby-text.

* gnu/packages/ruby.scm (ruby-text): New variable.

gnu: Add ruby-locale.

* gnu/packages/ruby.scm (ruby-locale): New variable.

gnu: Add ruby-power-assert.

* gnu/packages/ruby.scm (ruby-power-assert): New variable.

gnu: Add ruby-eventmachine.

* gnu/packages/ruby.scm (ruby-eventmachine): New variable.

gnu: Add ruby-permutation.

* gnu/packages/ruby.scm (ruby-permutation): New variable.

gnu: Add ruby-listen.

* gnu/packages/ruby.scm (ruby-listen): New variable.

gnu: Add ruby-rb-inotify.

* gnu/packages/ruby.scm (ruby-rb-inotify): New variable.

gnu: Add ruby-simplecov-html.

* gnu/packages/ruby.scm (ruby-simplecov-html): New variable.

gnu: Add ruby-ffi.

* gnu/packages/ruby.scm (ruby-ffi): New variable.