Ruby server can corrupt connections by putting ApplicationException in the middle of a response

1. Have a client make a call to a thrift server method that returns an invalid value for an enum
2. Have the client make another call to the same method that returns an invalid value for an enum

Expected: Thrift server responds with an ApplicationException for both calls
Actual: The thrift server responds with ApplicationException for the first call but then further calls can't be parsed by the client because there is unexpected data that the client cannot parse

I discovered this while writing a test case for THRIFT-3781 though it is the opposite problem.