Generated via git ls-files | xargs perl -pi -e "s/[Cc]opyright (?:\([Cc]\) )?((?\!$(date +%Y))\\d{4})(-\\d{4})?([, ][ \d]+)*(,|(?= ))/Copyright \\1-$(date +%Y),/g"

This is an entirely mechanically generated (chefstyle -a) change, to go
along with chef/chefstyle#5 . We should pick something and use it
consistently, and my opinion is that double quotes are the appropriate
thing.

Unreleased Chef 12.0.0 bug caught in testing where only the searching
upwards from PWD to find .chef in order to get the plugin path for knife
was busted.  The chef_config_dir was being used before load_config was
being called, so it was nil, which broke finding knife plugins.  This
was fixed by adding some lazy initialization of the config_loader object
itself and the chef_config_dir.

The reset_config_loader! is added entirely to reset the global state for unit
testing.  This whole class is a bit horrible and needs to have all its
global state removed from it, class methods removed, class ivars and the
class-variable-in-a-class-method-for-inheritance-lolwut needs to be removed.

Unfortunately, that requires some delicate surgery because Chef::Knife
gets used as a public API, and is beyond the scope of gettting Chef 12
shipped.

To resolve a chicken/egg issue with the logger being configured *after*
the config is located and read, knife will now check for a KNIFE_DEBUG
variable and initialize the logger to debug early in the startup process
when that variable is set.

`knife.rb` is not deprecated at this time.

The precedence of directories is the same. Directories are searched in
the same order, so that the presence of config.rb in a low precedence
directory, e.g., `~/.chef/config.rb` does not prevent knife from loading
a knife.rb located in a higer precedence directory, e.g.,
`$PWD/.chef/knife.rb`.