When running the test 'vtkCommonCoreTcl-TestSetGet',
clang's -fsanitize=bool complained:

runtime error: load of value 37, which is not a valid value for type 'bool'

The code called resize() on an stl vector which ended up using the default
constructor (which didn't initialize any ivars) and then subsequent new items
(I think) were copied from this one prototype by
IVFDataSetInfo::IVFDataSetInfo(const IVFDataSetInfo &ivfci)
which then copied the randomly-initialized bool into another bool,
and thus the error.  Fixed by zeroing everything in the default ctor.

Change-Id: Icd1a8c1b6a6eb84b525048b0177910f2a7d2f855