Bug Fix: Segfault on nenv_del() after using undef
Bug Fix: Segfault on nenv_del() after using undef

The memory wasn't being reallocated to accomidate the new empty
space. When nenv_del was being run on an environment that had undef
used on it, it tried to free already freed memory causing a segfault.

dragonrider23/nitrogen,dragonrider23/nitrogen