recovery: check node before try to connect to

This check exist in the old code but was accidentally refactored out by some
ghost commit.

Check node validity before connecting will save a lot of unnecessary network
traffic during recovery. Let's summon it back.

Signed-off-by: Liu Yuan <namei.unix@gmail.com>
Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
zk: remove annoying debug information

ZNONODE and ZNODEEXISTS are very high volume operation error code. And not
useful even for debug. So just git rid of them.

Signed-off-by: Liu Yuan <namei.unix@gmail.com>
Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
lib: remove unused macros in sha1.c

Signed-off-by: Liu Yuan <namei.unix@gmail.com>
Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
collie: clean up error messages

- don't duplicate error message in collie_exec_req
- print oid in vdi_check failure

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