Don't attempt logging in on a PREAUTH connection

Node-imap already correctly recorded state for PREAUTH connections,
but attempted to login anyway, which results in a timeout, as it waits
for the connection to get into a state it can never reach.

lib/imap.js

@@ -145,25 +145,32 @@ ImapConnection.prototype.connect = function(loginCb) {
   });
 
   state.conn.on('ready', function() {
-    // First get pre-auth capabilities, including server-supported auth
-    // mechanisms
+    var checkedNS = false;
+    var redo = function(err) {
+      if (err)
+        return loginCb(err);
+      // Next, get the list of available namespaces if supported (RFC2342)
+      if (!checkedNS && self._serverSupports('NAMESPACE')) {
+        // Re-enter this function after we've obtained the available
+        // namespaces
+        checkedNS = true;
+        return self._send('NAMESPACE', redo);
+      }
+      // Lastly, get the top-level mailbox hierarchy delimiter used by the
+      // server
+      self._send('LIST "" ""', loginCb);
+    };
+    // First, get the supported (pre-auth or otherwise) capabilities:
     self._send('CAPABILITY', function() {
-      // Next, attempt to login
-      var checkedNS = false;
-      self._login(function redo(err) {
-        if (err)
-          return loginCb(err);
-        // Next, get the list of available namespaces if supported (RFC2342)
-        if (!checkedNS && self._serverSupports('NAMESPACE')) {
-          // Re-enter this function after we've obtained the available
-          // namespaces
-          checkedNS = true;
-          return self._send('NAMESPACE', redo);
-        }
-        // Lastly, get the top-level mailbox hierarchy delimiter used by the
-        // server
-        self._send('LIST "" ""', loginCb);
-      });
+      // No need to attempt the login sequence if we're on a PREAUTH
+      // connection.
+      if (state.status != STATES.AUTH) {
+        // First get pre-auth capabilities, including server-supported auth
+        // mechanisms
+        self._login(redo);
+      } else {
+        redo();
+      };
     });
   });