Make "make dist" work with the new Erlang stuff.


git-svn-id: https://svn.apache.org/repos/asf/incubator/thrift/trunk@666500 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/lib/Makefile.am b/lib/Makefile.am
index 448dabd..09236ce 100644
--- a/lib/Makefile.am
+++ b/lib/Makefile.am
@@ -24,4 +24,5 @@
   perl  \
   php   \
   rb    \
+  erl   \
   st