merge revision(s) 43676: [Backport #8439]

	* test/openssl/test_cipher.rb (test_aes_gcm_wrong_tag): Don't use
	  String#succ because it can make modified (wrong) auth_tag longer
	  than 16 bytes.  The longer auth_tag makes that
	  EVP_CIPHER_CTX_ctrl (and internally aes_gcm_ctrl) fail.
	  [ruby-core:55143] [Bug #8439] reported by Vit Ondruch.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_0_0@44566 b2dd03c8-39d4-4d8f-98ff-823fe69b080e