[server] minor pointer typo fix
[server] minor memory leak fix for invalid FORCE_NAT var in access.conf

This commit fixes the following leak found by valgrind:

==6241== 568 bytes in 1 blocks are still reachable in loss record 1 of 1
==6241==    at 0x4C2A2DB: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==6241==    by 0x551537A: __fopen_internal (iofopen.c:73)
==6241==    by 0x118C8E: parse_access_file (access.c:1143)
==6241==    by 0x10F134: main (fwknopd.c:250)
[server] make sure clean_exit() is called on any add_acc_b64_string() errs
[server] call clean_exit() on add_acc_string() error
[server] call clean_exit() on expand_acc_string_list() error
[test suite] updated --gdb mode to run the first found fwknop command from an output/*.test file
[test suite] add Rjindael HMAC --no-ipt-check-support test for udp/53
[test suite] added iptables OUTPUT chain test