merge revision(s) 40304: [Backport #8240]

	* ext/openssl/ossl_ssl.c: Correct shutdown behavior w.r.t GC.

	* test/openssl/test_ssl.rb: Add tests to verify correct behavior.
	[Bug #8240] Patch provided by Shugo Maeda. Thanks!


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_0_0@40387 b2dd03c8-39d4-4d8f-98ff-823fe69b080e