Fix reduce_allocation().

alloc->list.last was repeatedly freed.

Test: built without seeing warnings.
Change-Id: Ia8b2f9d4b8ba9fbe13fae5d7a0a4d526ddc863d6
diff --git a/ext4_utils/allocate.c b/ext4_utils/allocate.c
index 00f2203..5f6347d 100644
--- a/ext4_utils/allocate.c
+++ b/ext4_utils/allocate.c
@@ -255,6 +255,7 @@
 			len -= last_reg->len;
 			if (reg) {
 				reg->next = NULL;
+				alloc->list.last = reg;
 			} else {
 				alloc->list.first = NULL;
 				alloc->list.last = NULL;