http: Remove socket from agent on error

Potential fix for nodejs#3236

lib/http.js

@@ -969,6 +969,18 @@ Agent.prototype.createSocket = function(name, host, port) {
     self.removeSocket(s, name, host, port);
   }
   s.on('close', onClose);
+
+  var onError = function(er) {
+    if (this._httpMessage) {
+      this._httpMessage.emit('error', er);
+    } else {
+      // This socket is broken, but we don't actually care about it
+      // at the time.  Just throw it away as if the socket had closed.
+      onClose();
+    }
+  };
+  s.on('error', onError);
+
   var onRemove = function() {
     // We need this function for cases like HTTP "upgrade"
     // (defined by WebSockets) where we need to remove a socket from the pool
@@ -977,6 +989,7 @@ Agent.prototype.createSocket = function(name, host, port) {
     s.removeListener('close', onClose);
     s.removeListener('free', onFree);
     s.removeListener('agentRemove', onRemove);
+    s.removeListener('error', onError);
   }
   s.on('agentRemove', onRemove);
   return s;