Fix close connection to imap server

lib/passport-imap/strategy.js

@@ -62,16 +62,20 @@ Strategy.prototype.authenticate = function(req, options) {
       var user = self._success_callback(this, imap);
       if (!user.id) {
         console.log("Success fallback must return an object with id parameter!");
+        imap.end();
         return self.fail("Success fallback must return an object with id parameter!");
       }
       self.success(user, "success");
+      imap.end();
     } else {
       console.log("Success fallback is required to generate the user!");
+      imap.end();
       return self.fail("Success fallback is required to generate the user!");
     }
   });
   imap.connect();
   imap.once('error', function(err) {
+    imap.end();
     return self.fail("Invalid credantials");
   });
 }
@@ -79,5 +83,5 @@ Strategy.prototype.authenticate = function(req, options) {
 
 /**
  * Expose `Strategy`.
- */ 
-module.exports = Strategy;
\ No newline at end of file
+ */
+module.exports = Strategy;