deb: remove duplicated database sections
deb: remove duplicated database sections

It seems that "Package"s uses "Section: database" in "Source" section
as the default "Section".

I counldn't find the behavior in the following Debian Policy Manual
sections:

  * http://www.debian.org/doc/debian-policy/ch-archive.html#s-subsections
  * http://www.debian.org/doc/debian-policy/ch-controlfields.html#s-f-Source

But it will be true because an official Debian developer's diff says
it.

[groonga-dev,01930]

Patch by Hideki Yamane. Thanks!!!

komainu8/groonga,komainu8/groonga,groonga/groonga,naoa/groonga,cosmo0920/groonga,redfigure/groonga,naoa/groonga,cosmo0920/groonga,komainu8/groonga,kenhys/groonga,kenhys/groonga,groonga/groonga,myokoym/groonga,naoa/groonga,cosmo0920/groonga,redfigure/groonga,myokoym/groonga,groonga/groonga,naoa/groonga,hiroyuki-sato/groonga,redfigure/groonga,cosmo0920/groonga,hiroyuki-sato/groonga,naoa/groonga,naoa/groonga,cosmo0920/groonga,myokoym/groonga,redfigure/groonga,myokoym/groonga,kenhys/groonga,redfigure/groonga,kenhys/groonga,myokoym/groonga,kenhys/groonga,komainu8/groonga,hiroyuki-sato/groonga,hiroyuki-sato/groonga,groonga/groonga,cosmo0920/groonga,naoa/groonga,myokoym/groonga,hiroyuki-sato/groonga,groonga/groonga,komainu8/groonga,redfigure/groonga,redfigure/groonga,hiroyuki-sato/groonga,cosmo0920/groonga,hiroyuki-sato/groonga,komainu8/groonga,naoa/groonga,groonga/groonga,groonga/groonga,cosmo0920/groonga,myokoym/groonga,kenhys/groonga,groonga/groonga,komainu8/groonga,kenhys/groonga,komainu8/groonga,myokoym/groonga,redfigure/groonga,hiroyuki-sato/groonga,kenhys/groonga