Use calloc() instead of malloc(n * s) followed by memset().

From Jean-Philippe Ouellet.

doc/CONTRIBUTORS

@@ -99,6 +99,7 @@ you believe you should be listed, please send a note to sudo@sudo.ws.
     Nieusma, Jeff
     Nikitser, Peter A.
     Nussel, Ludwig
+    Ouellet, Jean-Philippe
     Paquet, Eric
     Paradis, Chantal
     Percival, Ted

plugins/sudoers/auth/pam.c

@@ -315,9 +315,8 @@ converse(int num_msg, PAM_CONST struct pam_message **msg,
     int ret = PAM_AUTH_ERR;
     debug_decl(converse, SUDO_DEBUG_AUTH)
 
-    if ((*response = malloc(num_msg * sizeof(struct pam_response))) == NULL)
+    if ((*response = calloc(num_msg, sizeof(struct pam_response))) == NULL)
 	debug_return_int(PAM_SYSTEM_ERR);
-    memset(*response, 0, num_msg * sizeof(struct pam_response));
 
     for (pr = *response, pm = *msg, n = num_msg; n--; pr++, pm++) {
 	type = SUDO_CONV_PROMPT_ECHO_OFF;