Reverting mime type fix to previous code.

It nullifies sla #2121 :-( which led to the regressions sla #4303 and sla #4103
In essence, this revert should make mime type detection work for all but ppt and xls files in webdav. The latter will be treated as .doc files.

Change-Id: I350d2561be15e5d7abbca6b234fa963bc9798a6e
Merge commit 'refs/changes/30/630/1' of ssh://gerrit.tuleap.net:29418/tuleap into HEAD

* ssh://gerrit.tuleap.net:29418/tuleap:
  Reverting mime type fix to previous code.

Change-Id: I8a8244d3ac4826ba758e3559dcc3483f35e7be76
Tuleap 6.2.99.18

Change-Id: I674afd1612f3995bff8c877e2c87763066ab5957