Since python2.6, python has a proper ternary construct "A if PRED else
B". The older idiom "PRED and A or B" has a hidden trap - when A is
itself false, the result is (unexpectedly) B.
This change removes all cases of the older construct found using a
trivial git grep " and .* or " - except one case in oslo common
code (fixed in oslo upstream).
Change-Id: I24461f4328e188c8983ad574495e11e033ec5ba4