ryu.cfg: re-export some more stuff for convenience

Signed-off-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
allow overriding argv and progname

this will be used by the comming 'ryu' command.

Signed-off-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
pip-requires: require oslo.config >= 1.2.0

specifically we want their commit de803cdf
(Change-Id: If712e1d51c1e1329093acb16ed6a84e9f0baf8c1)
for stable order of cli options.
the following sub-command commits rely on it.

Signed-off-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
add bin/ryu

this new command takes a sub-command name as its first positional argument
and passes the rest of arguments to the corresponding sub-module.
for example, 'run' sub-command is an equivalent to bin/ryu-manager.

this commit does not replace the existing commands like ryu-manager.
this merely adds new ways to invoke the functionalities.

Signed-off-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
add bin/ryu to PYLINT_INCLUDE

Signed-off-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
document ryu command

Signed-off-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp>