Ignore executing install/remove scripts if XBPS_TARGET_ARCH is set.

Instead a two stage approach is necessary when packages for target arch
are installed:

	- XBPS_TARGET_ARCH=arch xbps-install foo <- only unpack
	- xbps-reconfigure -a <- configure natively or via an emulator

lib/transaction_commit.c

@@ -296,12 +296,16 @@ xbps_transaction_commit(struct xbps_handle *xhp)
 				goto out;
 		}
 	}
-	prop_object_iterator_reset(iter);
-
 	/* if there are no packages to install or update we are done */
 	if (!update && !install)
 		goto out;
 
+	/* if installing packages for target_arch, don't configure anything */
+	if (xhp->target_arch && strcmp(xhp->native_arch, xhp->target_arch))
+		goto out;
+
+	prop_object_iterator_reset(iter);
+
 	/*
 	 * Configure all unpacked packages.
 	 */