[Setup] mimetype text/x-web-markdown and migration to 2.5.3

[Lucia Colombo]

Hi all
I have migrated some sites to 2.5.3 on a windows platform, and everything 
was looking fine until I realized I could not import an exported site in 
such environment (self-to-self or anyway same platform/release).
I had the errors saying that  text/-x-web-mardown and text/x-web-mardown 
were not registered, as per ticket 6695 of  Plone Trac.
I did add the two mimetypes to the mimetypes registry and then re-exported 
the site, but still the import process fails, this time just because 
text/-x-web-mardown is not registered. But as far as I can see, it is 
registered now.
Is there anything else I should do when adding a mimetype to the registry? I 
think I did it correct and checked again and again... to be sure I was doing 
it right I created a new test plone site in the same instance and 
copy&pasted the entries for each mimetype from the newly created one (which 
is listing the mimetypes of course) to my existing-upgraded-from-2.5.2 site.

Thanks&bye
Lucia