handle closing by window manager (:cancel event) (bnc#891550)

- setting "FAKE_BASE_PRODUCT" environment variable enables
  mocking SLES12 base system for easy testing on non-SLES12 systems
- 3.1.100
do not restore the old state when abort is not confirmed
better :cancel to :abort conversion
better :cancel to :abort conversion
Merge pull request #142 from yast/cancel_event

Handle closing by window manager (:cancel event) (bnc#891550)