configure: remove unused variable

Signed-off-by: Liu Yuan <namei.unix@gmail.com>
Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
configure: use HAVE_TRACE macro

Signed-off-by: Liu Yuan <namei.unix@gmail.com>
Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
collie: print VIDs in various vdi operations

Priting VIDs after various operations by "collie vdi" is useful for
frontend software which wraps collie. Because detecting changed VIDs
with an output of "collie vdi list" is costly, printing changed VIDs
when the change happens is an effective way.

Signed-off-by: Hitoshi Mitake <mitake.hitoshi@lab.ntt.co.jp>
Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
sheep: remove a needless conditional branch

Current create_cluster() has a conditional branch which depends on
cluster drivers have their own get_local_addr(). If every cluster
driver has their own one, the branch is needless.

Signed-off-by: Hitoshi Mitake <mitake.hitoshi@lab.ntt.co.jp>
Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>