TNonBlocking handling of TSockets in error state is incorrect after fd is closed

Opening a pull request for https://github.com/apache/thrift/pull/1217/files.

In the future please follow the instructions at https://thrift.apache.org/docs/HowToContribute to open a Jira ticket and then open a pull request referencing that ticket by putting the jira ticket (THRIFT-nnnn) at the beggining of the PR description. Thanks.