RUSTSEC-2018-0003 Possible double free during unwinding in SmallVec::insert_many

If an iterator passed to SmallVec::insertmany panicked in Iterator::next, destructors were run during unwinding while the vector was in an inconsistent state, possibly causing a double free a destructor running on two copies of the same value. This is fixed in smallvec 0.6.3 by ensuring that the...