Plug a memory leak

Addressing:
openscap-1.3.0_alpha3/src/OVAL/probes/probe-api.c:1262: alloc_fn:
Storage is returned from allocation function "SEXP_list_first".
openscap-1.3.0_alpha3/src/OVAL/probes/SEAP/sexp-manip.c:1004:9:
alloc_fn: Storage is returned from allocation function "SEXP_ref".
openscap-1.3.0_alpha3/src/OVAL/probes/SEAP/sexp-manip.c:1619:9:
alloc_fn: Storage is returned from allocation function "SEXP_new".
openscap-1.3.0_alpha3/src/OVAL/probes/SEAP/sexp-manip.c:1593:16:
alloc_fn: Storage is returned from allocation function "malloc".
openscap-1.3.0_alpha3/src/OVAL/probes/SEAP/sexp-manip.c:1593:16:
var_assign: Assigning: "s_exp" = "malloc(16UL)".
openscap-1.3.0_alpha3/src/OVAL/probes/SEAP/sexp-manip.c:1602:9:
return_alloc: Returning allocated memory "s_exp".
openscap-1.3.0_alpha3/src/OVAL/probes/SEAP/sexp-manip.c:1619:9:
var_assign: Assigning: "s_exp_r" = "SEXP_new()".
openscap-1.3.0_alpha3/src/OVAL/probes/SEAP/sexp-manip.c:1625:9:
return_alloc: Returning allocated memory "s_exp_r".
openscap-1.3.0_alpha3/src/OVAL/probes/SEAP/sexp-manip.c:1004:9:
return_alloc_fn: Directly returning storage allocated by "SEXP_ref".
openscap-1.3.0_alpha3/src/OVAL/probes/probe-api.c:1262: var_assign:
Assigning: "tmp" = storage returned from "SEXP_list_first(ent_name)".
openscap-1.3.0_alpha3/src/OVAL/probes/probe-api.c:1264: var_assign:
Assigning: "ent_name" = "tmp".
openscap-1.3.0_alpha3/src/OVAL/probes/probe-api.c:1266: noescape:
Resource "ent_name" is not freed or pointed-to in "SEXP_stringp".
openscap-1.3.0_alpha3/src/OVAL/probes/SEAP/sexp-manip.c:630:34:
noescape: "SEXP_stringp(SEXP_t const *)" does not free or save its
parameter "s_exp".
openscap-1.3.0_alpha3/src/OVAL/probes/probe-api.c:1268: leaked_storage:
Variable "tmp" going out of scope leaks the storage it points to.
openscap-1.3.0_alpha3/src/OVAL/probes/probe-api.c:1268: leaked_storage:
Variable "ent_name" going out of scope leaks the storage it points to.

Author: jan-cerny

src/OVAL/probes/probe-api.c

@@ -1264,6 +1264,7 @@ char *probe_ent_getname(const SEXP_t * ent)
 		ent_name = tmp;
 
 		if (!SEXP_stringp(ent_name)) {
+			SEXP_free(ent_name);
 			errno = EINVAL;
 			return NULL;
 		}