Delete code generators after using them.

This has been leaking memory in the compiler, but it has also been
preventing the dynamic generators destructors from being called.
This can prevent a stream from being flushed properly.


git-svn-id: https://svn.apache.org/repos/asf/incubator/thrift/trunk@665586 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/compiler/cpp/src/main.cc b/compiler/cpp/src/main.cc
index 80da53a..e44c9b3 100644
--- a/compiler/cpp/src/main.cc
+++ b/compiler/cpp/src/main.cc
@@ -962,6 +962,7 @@
       } else {
         pverbose("Generating \"%s\"\n", iter->c_str());
         generator->generate_program();
+        delete generator;
       }
     }