fix syntax error in deepcopy() method for v0.20.0
Client: netstd
Patch: Sven Roederer

This closes #2993
diff --git a/compiler/cpp/src/thrift/generate/t_netstd_generator.cc b/compiler/cpp/src/thrift/generate/t_netstd_generator.cc
index 1a27c0c..03c2cb9 100644
--- a/compiler/cpp/src/thrift/generate/t_netstd_generator.cc
+++ b/compiler/cpp/src/thrift/generate/t_netstd_generator.cc
@@ -1103,7 +1103,7 @@
       out << endl << indent() << "{" << endl;
       indent_up();
     } else {
-      out << endl;
+      out << ";" << endl;
     }
 
     for (m_iter = members.begin(); m_iter != members.end(); ++m_iter) {