THRIFT-780. php: Prevent aborts due to simultaneous exceptions

THRIFT-780. php: Prevent aborts due to simultaneous exceptions

The bug was triggered when flush() threw an exception in the
PHPOutputTransport destructor.

The PHPOutputTransport in thrift_protocol_write_binary() wasn't
constructed inside of the try block, so exceptions thrown when it was
auto-flushing in the destructor were calling terminate().

Move the transport construction inside of the try block, and add an
explicit flush before the transport is destroyed (since throwing an
exception from a destructor is generally a bad thing).

Patch: David Reiss

git-svn-id: https://svn.apache.org/repos/asf/incubator/thrift/trunk@984815 13f79535-47bb-0310-9956-ffa450edef68