Since 1.9, driver specific log tag options
`syslog-tag`
`gelf-tag`
`fluentd-tag`
have been deprecated in favor of the generic tag
option which is standard across different logging
drivers.
This fix removed the deprecated driver specific
log tag options of `syslog-tag`, `gelf-tag`,
`fluentd-tag` for 1.12 and updated the docs.
Signed-off-by: Yong Tang <yong.tang.github@outlook.com>
Upstream-commit: a20b02b9158c283402d174926c84e657e53b17a1
Component: engine
979a878be3