drop trailing '.' from DESCRIPTIONs overlay-wide

repoman depected them as:

  DESCRIPTION.punctuation       1
   net-misc/htsn/htsn-0.1.0.ebuild: DESCRIPTION ends with a '.' character

Fixed by the following tiny script:
  https://github.com/trofi/gentoo-qa/blob/master/check_description.sh

Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>