Ensure we activate the "daemons launched" state when only the HNP is left or else we will hang.

cmr:v1.7.3:reviewer=jsquyres
don't call OMPI_REQUEST_INIT in req constructor

Calling OMPI_REQUEST_INIT puts the request into an _INACTIVE state
instead of an _INVALID state, which we don't want if it's been
simply been constructed, e.g., in a free_list.  Without this change a
future change to call destructors at free list destruction time will
result in request dtor state assertion failures.

Reviewed-by: bosilca

cmr=v1.7.4:reviewer=bosilca
call element destructors in ompi_free_list_destruct

The free list code called the constructor for each object it
slab allocated in ompi_free_list_grow.  This permits free list-managed
elements to safely allocate/deallocate resources in their
constructors/destructors without leaking.

It's probably best to let this soak on the trunk a little while before
moving it over to v1.7.

Reviewed-by: bosilca

cmr=v1.7.4:reviewer=bosilca