do proper checking for a pass not existing. fixes #671

Author: jcrugzz

lib/http-proxy/index.js

@@ -143,7 +143,7 @@ ProxyServer.prototype.before = function(type, passName, callback) {
     if(v.name === passName) i = idx;
   })
 
-  if(!i) throw new Error('No such pass');
+  if(i === false) throw new Error('No such pass');
 
   passes.splice(i, 0, callback);
 };
@@ -158,7 +158,7 @@ ProxyServer.prototype.after = function(type, passName, callback) {
     if(v.name === passName) i = idx;
   })
 
-  if(!i) throw new Error('No such pass');
+  if(i === false) throw new Error('No such pass');
 
   passes.splice(i++, 0, callback);
 };