MFH: r416751

Add a patch to fix sudo bug #743 that causes a bug where it dereference
a NULL pointer when it looks up a negative cached entry which is stored
as a NULL passwd or group struct pointer

PR: 208198
Submitted by: Fredrik Eriksson <fredrik.eriksson@loopia.se>
Obtained from: https://www.sudo.ws/repos/sudo/rev/1d13341d53ec
Sponsored by: Rubicon Communications (Netgate)
Approved by: ports-secteam (feld)