[PSA] cros_workon cli getting a bit more strict

[Mike Frysinger]

cros_workon currently accepts common options anywhere.  so you can write:

  $ cros_workon --board=foo list

or you can write:

  $ cros_workon list --board=foo

we're killing off support for the latter.

this syntax is relying on internal behavior of python modules that no longer works.  it's not clear we can easily maintain this syntax w/out a not-insignificant amount of code, so we're looking to just drop it and be done.

this does *not* impact cros_workon-$BOARD wrapper scripts.

-mike