Getpwent() and getservent() can wind up calling free() with

an invalid pointer if a call to yp_first() fails.  Closes PR # 964,
and possibly # 952.

lib/libc/gen/getpwent.c

@@ -650,7 +650,6 @@ _havemaster(char *_pw_yp_domain)
 
 	if (yp_first(_pw_yp_domain, "master.passwd.byname",
 		&key, &keylen, &result, &resultlen)) {
-		free(result);
 		return 0;
 	}
 	free(result);

lib/libc/net/getservent.c

@@ -78,7 +78,6 @@ _getypservent(line)
 			free(key);
 		if ((rv = yp_first(yp_domain, "services.byname", &key, &keylen,
 			     &result, &resultlen))) {
-			free(result);
 			serv_stepping_yp = 0;
 			return(0);
 		}