to get last error on the current thread. And should report
  errors are on the stack while OpenSSL.debug is true.

* ext/openssl/ossl.c (ossl_get_errors): new method for debugging
  this library.

* ext/openssl/ossl_ssl.c (ossl_sslctx_set_ciphers): fix error message.

* ext/openssl/ossl_x509req.c (ossl_x509req_set_attributes): get rid
  of unused variable.

* ext/openssl/ossl_x509store.c (ossl_x509store_initialize): should
  set @time to avoid warning.

* ext/openssl/ossl_x509store.c (ossl_x509store_set_default_paths,
  X509_STORE_add_cert, X509_STORE_add_crl): should raise error if
  wrapped functions failed.

* test/openssl/test_x509store.rb: add test for errors.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_8@9110 b2dd03c8-39d4-4d8f-98ff-823fe69b080e