Revert "packages: add ubuntu:release"
Revert "packages: add ubuntu:release"

This reverts commit a0b6fd87a18f4794dacf3322f4ae4746c3dec5c8.

This is needless.

groonga/groonga,naoa/groonga,kenhys/groonga,groonga/groonga,komainu8/groonga,groonga/groonga,komainu8/groonga,kenhys/groonga,komainu8/groonga,naoa/groonga,komainu8/groonga,naoa/groonga,komainu8/groonga,groonga/groonga,naoa/groonga,naoa/groonga,kenhys/groonga,kenhys/groonga,groonga/groonga,groonga/groonga,groonga/groonga,groonga/groonga,komainu8/groonga,kenhys/groonga,komainu8/groonga,naoa/groonga,naoa/groonga,komainu8/groonga,kenhys/groonga,kenhys/groonga,naoa/groonga,kenhys/groonga