DRTVWR-418: Remove ThreadingMixin from our HTTPServer subclass.

It's possible that raising an exception in a worker thread -- even though
we're TRYING to suppress it -- is what's causing the process to terminate with
nonzero rc.

indra/llcorehttp/tests/test_llcorehttp_peer.py

@@ -40,7 +40,6 @@
 except ImportError:
     from StringIO import StringIO
 from BaseHTTPServer import HTTPServer, BaseHTTPRequestHandler
-from SocketServer import ThreadingMixIn
 
 from llbase.fastest_elementtree import parse as xml_parse
 from llbase import llsd
@@ -274,7 +273,7 @@ def log_error(self, format, *args):
             # Suppress error output as well
             pass
 
-class Server(ThreadingMixIn, HTTPServer):
+class Server(HTTPServer):
     # This pernicious flag is on by default in HTTPServer. But proper
     # operation of freeport() absolutely depends on it being off.
     allow_reuse_address = False
@@ -284,8 +283,7 @@ class Server(ThreadingMixIn, HTTPServer):
     # to stderr which annoys some.  Disable this override to get
     # default behavior which *shouldn't* cause the program to return
     # a failure status.
-    if not VERBOSE:
-      def handle_error(self, request, client_address):
+    def handle_error(self, request, client_address):
         print '-'*40
         print 'Ignoring exception during processing of request from',
         print client_address