merge revision(s) 45274,45278,45280,48097: [Backport #9424]

	* lib/openssl/ssl.rb: Explicitly whitelist the default
	  SSL/TLS ciphers. Forbid SSLv2 and SSLv3, disable
	  compression by default.
	  Reported by Jeff Hodges.
	  [ruby-core:59829] [Bug #9424]

	* test/openssl/test_ssl.rb: Reuse TLS default options from
	  OpenSSL::SSL::SSLContext::DEFAULT_PARAMS.

	* ext/openssl/lib/openssl/ssl.rb (DEFAULT_PARAMS): override
	  options even if OpenSSL::SSL::OP_NO_SSLv3 is not defined.
	  this is pointed out by Stephen Touset. [ruby-core:65711] [Bug #9424]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_0_0@48110 b2dd03c8-39d4-4d8f-98ff-823fe69b080e