Set current branch station after checking MAIN_COMPANY

This can happen if the user created the database from one computer, didn't
register the first branch (so MAIN_COMPANY parameter is still None) and tried
to access the same database from another station that wasn't registered yet.

By calling 'set_current_branch_station' after checking the MAIN_COMPANY
parameter we can avoid that.

Change-Id: Ibd0ec5aaa972e4ac24411de50b45de77db3ded3e