Fix a typo

Reviewed By: mcslee


git-svn-id: https://svn.apache.org/repos/asf/incubator/thrift/trunk@665488 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/compiler/cpp/src/thrifty.yy b/compiler/cpp/src/thrifty.yy
index ffdb2f8..c104a81 100644
--- a/compiler/cpp/src/thrifty.yy
+++ b/compiler/cpp/src/thrifty.yy
@@ -69,7 +69,7 @@
 %token<dconst> tok_dub_constant
 
 /**
- * Header keywoards
+ * Header keywords
  */
 %token tok_include
 %token tok_namespace