fix crash get new mail with no inbox r=sspitzer 51366

mailnews/imap/src/nsImapMailFolder.cpp

@@ -1719,6 +1719,8 @@ NS_IMETHODIMP nsImapMailFolder::GetNewMessages(nsIMsgWindow *aWindow)
     PRUint32 numFolders;
     rv = rootFolder->GetFoldersWithFlag(MSG_FOLDER_FLAG_INBOX, 1, &numFolders, getter_AddRefs(inbox));
   }
+  if (inbox)
+  {
     nsCOMPtr <nsIEventQueue> eventQ;
     NS_WITH_SERVICE(nsIEventQueueService, pEventQService, kEventQueueServiceCID, &rv); 
     if (NS_SUCCEEDED(rv) && pEventQService)
@@ -1726,6 +1728,7 @@ NS_IMETHODIMP nsImapMailFolder::GetNewMessages(nsIMsgWindow *aWindow)
                         getter_AddRefs(eventQ));
     inbox->SetGettingNewMessages(PR_TRUE);
     rv = imapService->SelectFolder(eventQ, inbox, this, aWindow, nsnull);
+  }
 
   return rv;
 }

mailnews/local/src/nsLocalMailFolder.cpp

@@ -2115,6 +2115,7 @@ NS_IMETHODIMP nsMsgLocalMailFolder::GetNewMessages(nsIMsgWindow *aWindow)
 		rv = rootFolder->GetFoldersWithFlag(MSG_FOLDER_FLAG_INBOX, 1, &numFolders, getter_AddRefs(inbox));
 	}
 
+  if (inbox)
     rv = localMailServer->GetNewMail(aWindow, nsnull, inbox, nsnull); 
   return rv;
 }