fix for 28942 nsILocalFile::Exists() returns a FILE_NOT_FOUND error.

r=pete@alphanumerica.com

xpcom/io/nsLocalFileUnix.cpp

@@ -925,9 +925,7 @@ nsLocalFile::Exists(PRBool *_retval)
     NS_ENSURE_ARG_POINTER(_retval);
     PRBool accessOK;
     *_retval = accessOK = (access(mPath, F_OK) == 0);
-    if (accessOK || errno == EACCES)
     return NS_OK;
-    return NSRESULT_FOR_ERRNO();
 }
 
 NS_IMETHODIMP

xpcom/io/nsLocalFileWin.cpp

@@ -1461,16 +1461,9 @@ nsLocalFile::Exists(PRBool *_retval)
     nsresult rv = ResolveAndStat( PR_TRUE );
     
     if (NS_SUCCEEDED(rv))
-    {
         *_retval = PR_TRUE;
-    }
     else 
-    {
         *_retval = PR_FALSE;
-        if (GetLastError() != ERROR_FILE_NOT_FOUND)
-            return NS_ERROR_FAILURE;
-    }
-    
     
     return NS_OK;
 }