TS-2167: Update apichecker.pl to give suggestions on additional deprecated APIs
added TS-2167
Fix the 4.0.1 relase
ci: fix experimental tag substitution

jenkins-job-builder emits 'None' for a missing key, so the configure
line was ending up as:

  ./configure --enable-experimental-plugins --enable-wccp --enable-debug None

Replace it with an empty string instead.
ci: shrink builders pollng period
finishing up the cleanup of the admin guide

pretty much done with cleanup in the admin guide: We're missing a couple
of links here and there, and the warnings we get from the .. XXX: stuff
is on purpose, because it's broken, and needs retouching. Please either
leave it intact, or fix the documentation.
TS-2165: Introduce cluster-wide logging stats

With this patch, we can see the logging status of whole cluster.

Signed-off-by: Yunkai Zhang <qiushu.zyk@taobao.com>