sheep: check join result in the joining node

This moves the join check from the master's sd_check_join_cb() to the
joining node's sd_join_handler().  With this patch, we can completely
remove join failure handling from the cluster drivers.

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

sd_check_join_cb doesn't check the joining node now.
sd_accept_handler is a better name.

Also, this renames join_request to join and join_response to accept
for each cluster driver.

Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
Signed-off-by: Liu Yuan <namei.unix@gmail.com>
tests/functional: replace sleep with _wait_for_sheep

This replaces sleep with _wait_for_sheep and fixes a false alarm of
some tests.

This also removes a iteration of the test internal 007.  We can do the
same thing by running the test 007 several times.

Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
Signed-off-by: Liu Yuan <namei.unix@gmail.com>
corosync: add helper to update join status

This improves code readability a bit.

Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
Signed-off-by: Liu Yuan <namei.unix@gmail.com>
clean up logger.h and util.h include

This also fixes a compiler error which happens when NDEBUG is not
defined.

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

The current log format is expected to be used for server daemons and
not appropriate for collie and sheepfs.  This patch introduces a
simpler formatter for them.

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