pull request #969 - dying in shared shop wall

Pull request by entrez, following up issue by k2:  when deciding
whether a shopkeeper should taken possession of dying heros invent,
check all rooms the hero is in rather than just the first.  Deals
with dying in a gap of a wall shared by two shops.

Original issue was about "place_object: <item> off map <0,0>" but
an earlier commit fixed that (I hope).  That commit had a typo in
the issue number and closed #965 (which was already closed) instead
of #969 (which this pull request reopened anyway).

Closes #969