[FIX] reversed order in which entries are deleted from _var_map and _rev_map because it was causing a double free error that was happening once in a while. We also commented the resizing of the matrix inside get_dbm_index. Replaced own swap with std::swap.
[FIX] reversed order in which entries are deleted from _var_map and _rev_map because it was causing a double free error that was happening once in a while. We also commented the resizing of the matrix inside get_dbm_index. Replaced own swap with std::swap.

seahorn/crab,seahorn/crab,caballa/crab