THRIFT-4376: fix more high impact coverity defects
Led to the discovery of incorrect lua socket error handling.

This closes #1405
diff --git a/lib/cpp/test/SecurityTest.cpp b/lib/cpp/test/SecurityTest.cpp
index 6eb1fe3..51ee427 100644
--- a/lib/cpp/test/SecurityTest.cpp
+++ b/lib/cpp/test/SecurityTest.cpp
@@ -255,11 +255,12 @@
                     % protocol2str(si) % protocol2str(ci));
 
                 mConnected = false;
+                // thread_group manages the thread lifetime - ignore the return value of create_thread
                 boost::thread_group threads;
-                threads.create_thread(bind(&SecurityFixture::server, this, static_cast<apache::thrift::transport::SSLProtocol>(si)));
+                (void)threads.create_thread(bind(&SecurityFixture::server, this, static_cast<apache::thrift::transport::SSLProtocol>(si)));
                 mCVar.wait(lock);           // wait for listen() to succeed
                 lock.unlock();
-                threads.create_thread(bind(&SecurityFixture::client, this, static_cast<apache::thrift::transport::SSLProtocol>(ci)));
+                (void)threads.create_thread(bind(&SecurityFixture::client, this, static_cast<apache::thrift::transport::SSLProtocol>(ci)));
                 threads.join_all();
 
                 BOOST_CHECK_MESSAGE(mConnected == matrix[ci][si],