dist/ubuntu: check lsb_release existance since it's not included minimal Debian installation
dist/ubuntu: check lsb_release existance since it's not included minimal Debian installation

Ubuntu has it in minimal installation but Debian doesn't, so add it.

Signed-off-by: Takuya ASADA <4ebfb6f510af412d6e89fefa3ab96d9c8b5e3fff@scylladb.com>
Message-Id: <1483003565-2753-1-git-send-email-4ebfb6f510af412d6e89fefa3ab96d9c8b5e3fff@scylladb.com>

raphaelsc/scylla,avikivity/scylla,scylladb/scylla,scylladb/scylla,duarten/scylla,scylladb/scylla,avikivity/scylla,raphaelsc/scylla,scylladb/scylla,duarten/scylla,avikivity/scylla,duarten/scylla,raphaelsc/scylla