[Tracker] html_filter generate a extra file

[Carles Briansó <cbrianso tinet org>]

The html_filter generate a extra file that contains a tags of the
original file.

Example:

I save a file named debian.html in home directory
Then the trackerd detect and added correctly
Later in the directory of debian.html, have a debian_t.txt that contain
a tags of debian.html file.

I see that the file is generated by htmless program.