libsepol/cil: destroy perm_datums when __cil_resolve_perms fails

When __cil_resolve_perms fails, it does not destroy perm_datums, which
leads to a memory leak reported by OSS-Fuzz with the following CIL
policy:

    (class cl01())
    (classorder(cl01))
    (type at02)
    (type tpr3)
    (allow at02 tpr3(cl01((s))))

Calling cil_list_destroy() fixes the issue.

Fixes: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=28466
Signed-off-by: Nicolas Iooss <nicolas.iooss@m4x.org>

libsepol/cil/src/cil_resolve_ast.c

@@ -146,6 +146,7 @@ static int __cil_resolve_perms(symtab_t *class_symtab, symtab_t *common_symtab,
 	return SEPOL_OK;
 
 exit:
+	cil_list_destroy(perm_datums, CIL_FALSE);
 	return rc;
 }