checkpolicy: destroy the class datum if it fails to initialize

require_class() allocate memory for its variable "class_datum_t *datum"
and calls symtab_init(&datum->permissions, PERM_SYMTAB_SIZE). If this
second call fails, datum is not freed.

Fix this memory leak.

Signed-off-by: Nicolas Iooss <nicolas.iooss@m4x.org>

checkpolicy/module_compiler.c

@@ -802,6 +802,7 @@ int require_class(int pass)
 	if ((datum = calloc(1, sizeof(*datum))) == NULL ||
 	    symtab_init(&datum->permissions, PERM_SYMTAB_SIZE)) {
 		yyerror("Out of memory!");
+		class_datum_destroy(datum);
 		return -1;
 	}
 	ret =