Description:
------------
different results from finfo_file and finfo_buffer

Scenario:
1. MS Excel-File stored in mySQL database LONGBLOB-Column
2. This binary data selected from database
3. This binary data stored to tempfile
4. mime-type sniffing done by finfo_buffer on binary data
   > result: application/octet-stream
5. mime-type sniffing done by finfo_file on tempfile
   > result: application/vnd.ms-excel

PROBLEM:
different result, dependent on used Fileinfo Function

Comment: The tempfile has NO extension like ".xls" that could be used as hint for mimetype-sniffing


Reproduce code:
---------------
<?PHP
...
      $tempFileName   = tempnam(sys_get_temp_dir(), "tempfile");
      $tempFileHandle = fopen($tempFileName, "w");
      fwrite($tempFileHandle, $attrib);
      fclose($tempFileHandle);
      // ensure that "extension=php_fileinfo.dll" is enabled in php.ini
      $finfo = finfo_open(FILEINFO_MIME_TYPE); // return mime type ala mimetype extension
      $fileContentsTypeBuf = finfo_buffer($finfo, $attrib, FILEINFO_MIME_TYPE);
      $fileContentsType = finfo_file($finfo, $tempFileName);
      finfo_close($finfo);
...

Expected result:
----------------
same result "application/vnd.ms-excel", independent from used Fileinfo Function (finfo_buffer or finfo_file)


Actual result:
--------------
different results 
"application/octet-stream" for finfo_buffer
"application/vnd.ms-excel" for finfo_file