THRIFT-1107. py: improvement for compiler-generated python for 'None' object comparisons

This patch switches from 'x != None' to 'x is not None' for a small performance boost.

Patch: Will Pierce

git-svn-id: https://svn.apache.org/repos/asf/thrift/trunk@1084661 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/compiler/cpp/src/generate/t_py_generator.cc b/compiler/cpp/src/generate/t_py_generator.cc
index b6b0ab4..dbeed5d 100644
--- a/compiler/cpp/src/generate/t_py_generator.cc
+++ b/compiler/cpp/src/generate/t_py_generator.cc
@@ -827,7 +827,7 @@
   for (f_iter = fields.begin(); f_iter != fields.end(); ++f_iter) {
     // Write field header
     indent(out) <<
-      "if self." << (*f_iter)->get_name() << " != None:" << endl;
+      "if self." << (*f_iter)->get_name() << " is not None:" << endl;
     indent_up();
     indent(out) <<
       "oprot.writeFieldBegin(" <<
@@ -1064,7 +1064,7 @@
     } else {
       f_service_ <<
         indent() << "  self._iprot = self._oprot = iprot" << endl <<
-        indent() << "  if oprot != None:" << endl <<
+        indent() << "  if oprot is not None:" << endl <<
         indent() << "    self._oprot = oprot" << endl <<
         indent() << "  self._seqid = 0" << endl <<
         endl;
@@ -1233,7 +1233,7 @@
       // Careful, only return _result if not a void function
       if (!(*f_iter)->get_returntype()->is_void()) {
         f_service_ <<
-          indent() << "if result.success != None:" << endl;
+          indent() << "if result.success is not None:" << endl;
           if (gen_twisted_) {
             f_service_ <<
               indent() << "  return d.callback(result.success)" << endl;
@@ -1248,7 +1248,7 @@
       vector<t_field*>::const_iterator x_iter;
       for (x_iter = xceptions.begin(); x_iter != xceptions.end(); ++x_iter) {
         f_service_ <<
-          indent() << "if result." << (*x_iter)->get_name() << " != None:" << endl;
+          indent() << "if result." << (*x_iter)->get_name() << " is not None:" << endl;
           if (gen_twisted_) {
             f_service_ <<
               indent() << "  return d.errback(result." << (*x_iter)->get_name() << ")" << endl;