Cleanup Gemfile

The :development group is pointless because Gemfile is relevant for
those who run ruby/openssl tests in this repository only, and not
included in the gem package. Let's list the test dependency in the top
level.

The rdoc library is now a bundled gem in Ruby master, not just in
Fedora's Ruby distributions.

Gemfile

@@ -1,11 +1,8 @@
 source "https://rubygems.org"
 
-group :development do
-  gem "rake"
-  gem "rake-compiler"
-  gem "test-unit", "~> 3.0", ">= 3.4.6"
-  gem "test-unit-ruby-core"
-  gem "prime"
-  # In the case of Ruby whose rdoc is not a default gem.
-  gem "rdoc"
-end
+gem "rake"
+gem "rake-compiler"
+gem "test-unit", "~> 3.0", ">= 3.4.6"
+gem "test-unit-ruby-core"
+gem "prime"
+gem "rdoc"