Fix logger issues

[lamont-granquist]

fix ohai logger problems.

i believe this gets the logic correct in that we want to configure the
logger when we're coming from the command line but want to skip it when
we're coming from chef or from other APIs that directly construct an
Ohai::System object.

i suspect this is what thom was trying to do by moving the
Ohai::Log.init call into the Ohai::Application class (which avoids it
being called entirely when Chef creates its Ohai::System object) here:

https://github.com/chef/ohai/pull/942/files

but that change broke the behavior where we were also supposed to skip
the rest of the configure_logging method in Ohai::System when run under
chef client.

I tried going down the route of having the Ohai::Application class
construct the Ohai::System object and then having it be the
responsibility of that caller to do configure_logging work.  However,
I suspect that the initializer in Ohai::System does way too much and
that the purpose of configuring the logger where it is, is that it
must be initialized in the middle of object creation before it goes on
and creates the Loader, the Runner, creates Hints and removes constants.

So, I went the route of threading a flag through the initializer so that
Ohai::System can know if its coming from the cli or not and behave
appropriately.

There's also quite a mess with the Ohai::Log class being passed around
to the workstation loader, and it initializes itself at class loading
time and Chef::Application will inject state into Ohai::Log.  I think
the eager initialization at class loading time is to not lose early
messages when run from the cli, but it means the Ohai::Log object is always
initialized, so that isn't useful for determining if we have come from the
cli or not.

[lamont-granquist]

@tas50 @cheeseplus i think this is more-or-less correct

[lamont-granquist]

optional hashes and named arguments in ruby #FML

[tas50]

Wanna add as simple test on that flag and look at the Travis failure

done

[lamont-granquist]

@tas50 @cheeseplus once more unto the breach, dear friends, once more