bitbake: hob: some settings in Hob are not remembered

bitbake: hob: some settings in Hob are not remembered

Some settings in Hob were not saved in Bitbake and they were not displayed
correcty in Hob, because Hob used some other variables with the extension "_HOB".
I have removed this, in order to have a consistency for the variables.
ALso, I called a function to load the extra variables saved in .hob/template_default.hob.

[YOCTO #3957]
(Bitbake rev: 0f62a12ef3fa4daf8f3a289c984115302b75c23d)

Signed-off-by: Cristiana Voicu <cristiana.voicu@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>