title: NodeJS: "ENOENT" warning messages with sessions
body: <p>I'm using node with the express-session and session-file-store packages.  The session data is stored as files in the root directory, using the session-file-store package.  However, now my logs are being clogged because the message <code>[session-file-store] will retry, error on last attempt: Error: ENOENT, open 'sessions/_jl2ijMBQHIvv8M1mYTcnFZGqwGo0t-v.json'</code> is appearing 5 times per session cookie accessed in a short burst.  What could be causing this error?  It's happening both on my windows development machine and on my ubuntu server.  It can't access the file apparently, but the sessions still work.</p>
  
  <p>Here is one of the bursts of errors I received:</p>
  
  <pre><code>[session-file-store] will retry, error on last attempt: Error: ENOENT, open 'sessions/tRI6WeZEO2Uyvr4ZaUGW6_CU32RjvFpW.json'
  [session-file-store] will retry, error on last attempt: Error: ENOENT, open 'sessions/tRI6WeZEO2Uyvr4ZaUGW6_CU32RjvFpW.json'
  [session-file-store] will retry, error on last attempt: Error: ENOENT, open 'sessions/tRI6WeZEO2Uyvr4ZaUGW6_CU32RjvFpW.json'
  [session-file-store] will retry, error on last attempt: Error: ENOENT, open 'sessions/tRI6WeZEO2Uyvr4ZaUGW6_CU32RjvFpW.json'
  [session-file-store] will retry, error on last attempt: Error: ENOENT, open 'sessions/tRI6WeZEO2Uyvr4ZaUGW6_CU32RjvFpW.json'
  </code></pre>