THRIFT-133. add missing file to makefile.am

git-svn-id: https://svn.apache.org/repos/asf/incubator/thrift/trunk@982359 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/compiler/cpp/Makefile.am b/compiler/cpp/Makefile.am
index 892b9a0..4e7b9c0 100644
--- a/compiler/cpp/Makefile.am
+++ b/compiler/cpp/Makefile.am
@@ -33,6 +33,7 @@
                  src/main.cc \
                  src/md5.c \
                  src/generate/t_generator.cc \
+                 src/generate/t_generator_registry.h \
                  src/globals.h \
                  src/main.h \
                  src/platform.h \