ensure syslogd is up before starting the build

test/schema.py uses log/syslog which requires a running syslog daemon
and the start script should guarantee it is up and running.
Add vtctld explorer plugin for etcd.
Merge pull request #253 from yaoshengzhe/fix_flaky_ci_test

ensure syslogd is up before starting the build
let travis build status ref master branch only
Merge pull request #258 from yaoshengzhe/fix_travis_badge_for_master

let travis build status ref master branch only
Merge pull request #257 from youtube/etcd-explorer

Add vtctld explorer plugin for etcd.
Merge branch 'master' into replication