Fix request #7116: Can't reply by mail to a tracker

The issue comes from the fact that we are using nested shebangs, wich
are supported only from kernel 2.6.27 (for details, see
https://lkml.org/lkml/2008/9/6/66).
- CentOS 5: Linux 2.6.18
- CentOS 6: Linux 2.6.32

Change-Id: I6438c715bedddf776b9d0bbe1922f391188029dd
Merge commit 'refs/changes/85/2685/2' of ssh://gerrit.tuleap.net:29418/tuleap into HEAD

* ssh://gerrit.tuleap.net:29418/tuleap:
  Fix request #7116: Can't reply by mail to a tracker

Change-Id: Ief98fe86d2383ede07586cb8154dcba1d6ef2fa2
This is Tuleap 7.2.99.20

Change-Id: I68b4473be6ca2b4f78e544eff7ef0b9280f55536