amqp_openssl: fix SSL_connect() status check
amqp_openssl: fix SSL_connect() status check

According to documentation SSL_connect() can return:
- 1 if handshake was successful or
- 0 or < 0 if handshake failed and connection was cleaned up or
  communcation error occurred

When nonblocking flag is set on the socket and handshake is in progress,
SSL_connect() retruns -1 and sets error SSL_ERROR_WANT_READ. The test
will then skip the switch() branch, and proceed forward with hanshake
procedure in unfinished state. This may lead to certificate verification
failure, as should the handshake be interrupted too soon, no server
certificates would be received.

hjzljp/rabbitmq-c,tempbottle/rabbitmq-c,jqk6/rabbitmq-c,sakishum/rabbitmq-c,soindy/rabbitmq-c,sakishum/rabbitmq-c,hjzljp/rabbitmq-c,kilinrax/rabbitmq-c,jqk6/rabbitmq-c,chenwenbin928/rabbitmq-c,kilinrax/rabbitmq-c,soindy/rabbitmq-c,kilinrax/rabbitmq-c,chenwenbin928/rabbitmq-c,chenwenbin928/rabbitmq-c,hjzljp/rabbitmq-c,alanxz/rabbitmq-c,jqk6/rabbitmq-c,soindy/rabbitmq-c,jqk6/rabbitmq-c,Haster2004/rabbitmq-c,Haster2004/rabbitmq-c,tempbottle/rabbitmq-c,tempbottle/rabbitmq-c,tempbottle/rabbitmq-c,alanxz/rabbitmq-c,Haster2004/rabbitmq-c,alanxz/rabbitmq-c,hjzljp/rabbitmq-c,sakishum/rabbitmq-c