fix uninitialized variable access in xqsort and xbsearch

This silences valgrind errors.

Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
Signed-off-by: Liu Yuan <namei.unix@gmail.com>
collie: fix the output of 'collie --help'

Without this patch, the output of 'collie --help' is as follows:

  $ collie --help
  Invalid command '--help'
  Try 'collie --help' for more information.

Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
Signed-off-by: Liu Yuan <namei.unix@gmail.com>
zookeeper: retry zk_create_seq_node on retryable error

This checks znodes in the zookeeper queue, and retries zoo_create()
when the requested znode is not created.

Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
Signed-off-by: Liu Yuan <namei.unix@gmail.com>
zookeeper: use offsetof to calculate offset

Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
Signed-off-by: Liu Yuan <namei.unix@gmail.com>
Revert "zk: delete zk node before join cluster"

This reverts commit 4f82a4a86e69a0081a54a811ebec615a42f16506.

Concurrent setup is broken by this patch.