This fixes a bug I introduced last night

net/base/cert_database_nss.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/base/cert_database.h"
 
 #include <cert.h>
 #include <certdb.h>
 #include <keyhi.h>
 #include <pk11pub.h>
@@ skipping 46 matching lines @@
     return ERR_NO_PRIVATE_KEY_FOR_CERT;
   }
   PK11_FreeSlot(slot);
 
   return OK;
 }
 
 int CertDatabase::AddUserCert(X509Certificate* cert_obj) {
   CERTCertificate* cert = cert_obj->os_cert_handle();
   PK11SlotInfo* slot = NULL;
-  std::string nickname;
 
   {
     crypto::AutoNSSWriteLock lock;
     slot = PK11_ImportCertForKey(
         cert,
         cert_obj->GetDefaultNickname(net::USER_CERT).c_str(),
         NULL);
   }
 
   if (!slot) {
@@ skipping 235 matching lines @@
   }
   return true;
 }
 
 bool CertDatabase::IsReadOnly(const X509Certificate* cert) const {
   PK11SlotInfo* slot = cert->os_cert_handle()->slot;
   return slot && PK11_IsReadOnly(slot);
 }
 
 }  // namespace net