When (re)allocating space for an array of pointers to char, use
sizeof(*list), not sizeof(**list). (i.e., sizeof(pointer) rather than
sizeof(char)).

It is possible that this buffer overflow is exploitable, but it was
added after RELENG_5 forked and hasn't been MFCed, so this will not
receive an advisory.

Submitted by: Vitezslav Novy
MFC after: 1 day