libselinux: abnormal branches may cause memory leakage.

[lujiev]

the func __policy_init() In the libselinux/src/audit2why.c
It maybe cause memory leak when the function returns 1 after invokes function calloc() and sepol_policy_file_create() successfully.

    avc = calloc(sizeof(struct avc_t), 1);
if (!avc) {
	...
	return 1;
}

if (sepol_policy_file_create(&pf) ||
    sepol_policydb_create(&avc->policydb)) {
	snprintf(errormsg, sizeof(errormsg), 
		 "policydb_init failed: %m\n");
	PyErr_SetString( PyExc_RuntimeError, errormsg);
	fclose(fp);
           ############maybe case a memory leak for avc #######
	return 1;
}
sepol_policy_file_set_fp(pf, fp);	
if (sepol_policydb_read(avc->policydb, pf)) {
	snprintf(errormsg, sizeof(errormsg), 
		 "invalid binary policy %s\n", curpolicy);
	PyErr_SetString( PyExc_ValueError, errormsg);
	fclose(fp);
            ############maybe case a memory leak for avc and pf #######
	return 1;
}
    ...