Add NETWORK_ERROR to switch statement

Summary: Add NETWOR_ERROR to switch so it doesn't fall into Invalid Exception block.

Differential Revision: D3282448

fbshipit-source-id: 2cc5d21e436e6ac8f2f6581d99341ac47cf5b023

folly/io/async/AsyncSocketException.h

@@ -96,6 +96,8 @@ class AsyncSocketException : public std::runtime_error {
         return "Could not bind";
       case SASL_HANDSHAKE_TIMEOUT:
         return "SASL handshake timeout";
+      case NETWORK_ERROR:
+        return "Network error";
       default:
         return "(Invalid exception type)";
     }