Remove "rescue" clause around "require 'openssl'"

Some `require 'openssl'` statements were surrounded by `rescue` blocks to deal with Ruby versions that did not support `OpenSSL::Digest::SHA1` or `OpenSSL::PKCS5`.

[As @jeremy explains](a6a0904fcb (commitcomment-8826666)) in the original commit:

> If jruby didn't have jruby-openssl gem, the require wouldn't work. Not sure whether either of these are still relevant today.

According to the [release notes for JRuby 1.7.13](http://www.jruby.org/2014/06/24/jruby-1-7-13.html):

> jruby-openssl 0.9.5 bundled

which means the above `rescue` block is not needed anymore.

All the Ruby versions supported by the current version of Rails provide those OpenSSL libraries, so Travis CI should also be happy by removing the `rescue` blocks.

---

Just to confirm, with JRuby:

    $ ruby --version #=> jruby 1.7.16.1 (1.9.3p392) 2014-10-28 4e93f31 on Java HotSpot(TM) 64-Bit Server VM 1.8.0_20-b26 +jit [darwin-x86_64]
    $ irb
    irb(main):001:0> require 'openssl' #=> true
    irb(main):002:0> OpenSSL::Digest::SHA1 #=> OpenSSL::Digest::SHA1
    irb(main):003:0> OpenSSL::PKCS5 # => OpenSSL::PKCS5

And with Ruby 2.1:

    $ ruby --version #=> ruby 2.1.2p95 (2014-05-08 revision 45877) [x86_64-darwin13.0]
    $ irb
    irb(main):001:0> require 'openssl' #=> true
    irb(main):002:0> OpenSSL::Digest::SHA1 #=> OpenSSL::Digest::SHA1
    irb(main):003:0> OpenSSL::PKCS5 #=> OpenSSL::PKCS5

actionpack/test/dispatch/cookies_test.rb

@@ -1,12 +1,5 @@
 require 'abstract_unit'
-
-begin
-  require 'openssl'
-  OpenSSL::PKCS5
-rescue LoadError, NameError
-  $stderr.puts "Skipping KeyGenerator test: broken OpenSSL install"
-else
-
+require 'openssl'
 require 'active_support/key_generator'
 require 'active_support/message_verifier'
 
@@ -1155,5 +1148,3 @@ class CookiesTest < ActionController::TestCase
       end
     end
 end
-
-end

activesupport/test/message_encryptor_test.rb

@@ -1,12 +1,5 @@
 require 'abstract_unit'
-
-begin
-  require 'openssl'
-  OpenSSL::Digest::SHA1
-rescue LoadError, NameError
-  $stderr.puts "Skipping MessageEncryptor test: broken OpenSSL install"
-else
-
+require 'openssl'
 require 'active_support/time'
 require 'active_support/json'
 
@@ -97,5 +90,3 @@ class MessageEncryptorTest < ActiveSupport::TestCase
     ::Base64.strict_encode64(bits)
   end
 end
-
-end

activesupport/test/message_verifier_test.rb

@@ -1,12 +1,5 @@
 require 'abstract_unit'
-
-begin
-  require 'openssl'
-  OpenSSL::Digest::SHA1
-rescue LoadError, NameError
-  $stderr.puts "Skipping MessageVerifier test: broken OpenSSL install"
-else
-
+require 'openssl'
 require 'active_support/time'
 require 'active_support/json'
 
@@ -41,11 +34,11 @@ class MessageVerifierTest < ActiveSupport::TestCase
     assert_equal @data, @verifier.verified(message)
     assert_equal @data, @verifier.verify(message)
   end
-  
+
   def test_verified_returns_false_on_invalid_message
     assert !@verifier.verified("purejunk")
   end
-  
+
   def test_verify_exception_on_invalid_message
     assert_raise(ActiveSupport::MessageVerifier::InvalidSignature) do
       @verifier.verify("purejunk")
@@ -90,5 +83,3 @@ class MessageVerifierTest < ActiveSupport::TestCase
     assert_equal exception.message, 'Secret should not be nil.'
   end
 end
-
-end