Don't require that the last character of the "DateTime" field of packed

messages is a null (0x00) byte. Some broken FidoNet software may include
a full 20 usable characters in their DateTime header field, like so:
"04 Feb 119  20:26:32" - representing February 4th, 2019.  Y2K. <sigh>

The DateTime won't be parsed fully correct, but at least the packet won't be
rejected outright because it is "Grunged". - for Alterego (ALTERANT)