Typically, the LANGUAGE has already been set in the run-language-page
step. But for languages like pt, we must know the territory.
* gnu/installer/newt/locale.scm (run-territory-page): Call ‘setenv’ for
the ‘LANGUAGE’ variable.
Change-Id: Ie6308c359e0bdb2d37fac0c844cfd879e96e231a