Corrected a wrong namespace comment

Summary: Pull Request resolved: https://github.com/facebook/folly/pull/912

Reviewed By: Orvid

Differential Revision: D9344568

Pulled By: yfeldblum

fbshipit-source-id: bcafaab895454f21c3005825003916d771210d33

folly/io/async/PasswordInFile.h

@@ -41,4 +41,4 @@ class PasswordInFile : public PasswordCollector {
   std::string password_;
 };
 
-} // namespace wangle
+} // namespace folly