Plug a memory leak.

Addressing:
12 bytes in 1 blocks are definitely lost in loss record 1 of 2
   at 0x4A0858C: memalign (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
   by 0x4A08651: posix_memalign (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
   by 0x4C8DC13: SEXP_val_new (sexp-value.c:38)
   by 0x4C8B2D0: SEXP_parse_kl_string (sexp-parser.c:1638)
   by 0x4C8D8EA: SEXP_parse (sexp-parser.c:525)
   by 0x4C858F4: SEAP_packet_recv (seap-packet.c:721)
   by 0x4C871CA: SEAP_recvmsg (seap.c:356)
   by 0x4C7E998: oval_probe_comm (oval_probe_ext.c:487)
   by 0x4C7FC5E: oval_probe_ext_eval (oval_probe_ext.c:1085)
   by 0x4C7FF19: oval_probe_ext_handler (oval_probe_ext.c:902)
   by 0x4C6EC02: oval_probe_query_object (oval_probe.c:285)
   by 0x4C6EE73: oval_probe_query_criteria (oval_probe.c:374)

16 bytes in 1 blocks are definitely lost in loss record 2 of 2
   at 0x4A0645D: malloc (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
   by 0x4C890DD: SEXP_new (sexp-manip.c:1593)
   by 0x4C8CB48: SEXP_parse (sexp-parser.c:490)
   by 0x4C858F4: SEAP_packet_recv (seap-packet.c:721)
   by 0x4C871CA: SEAP_recvmsg (seap.c:356)
   by 0x4C7E998: oval_probe_comm (oval_probe_ext.c:487)
   by 0x4C7FC5E: oval_probe_ext_eval (oval_probe_ext.c:1085)
   by 0x4C7FF19: oval_probe_ext_handler (oval_probe_ext.c:902)
   by 0x4C6EC02: oval_probe_query_object (oval_probe.c:285)
   by 0x4C6EE73: oval_probe_query_criteria (oval_probe.c:374)
   by 0x4C6EDAF: oval_probe_query_criteria (oval_probe.c:427)
   by 0x4C6EDAF: oval_probe_query_criteria (oval_probe.c:427)