THRIFT-2594 JS Compiler: Single quotes are not being escaped in constants.

Patch: Thomas Lazar
diff --git a/compiler/cpp/src/generate/t_js_generator.cc b/compiler/cpp/src/generate/t_js_generator.cc
index 7f53016..32cb162 100644
--- a/compiler/cpp/src/generate/t_js_generator.cc
+++ b/compiler/cpp/src/generate/t_js_generator.cc
@@ -74,6 +74,8 @@
      } else {
        out_dir_base_ = "gen-js";
      }
+
+     escape_['\''] = "\\'";
   }
 
   /**