libsnapshot: Fix broken iterator in CompressedSnapshotReader.

Bug: NA
Test: apply full OTA with VABC
Change-Id: I9173ac1c6fb601a6f9e0bfb935d7908e0f234f0f
diff --git a/fs_mgr/libsnapshot/snapshot_reader.cpp b/fs_mgr/libsnapshot/snapshot_reader.cpp
index 0ac79a1..b56d879 100644
--- a/fs_mgr/libsnapshot/snapshot_reader.cpp
+++ b/fs_mgr/libsnapshot/snapshot_reader.cpp
@@ -91,6 +91,7 @@
     while (!op_iter_->Done()) {
         const CowOperation* op = &op_iter_->Get();
         if (op->type == kCowLabelOp || op->type == kCowFooterOp) {
+            op_iter_->Next();
             continue;
         }
         if (op->new_block >= ops_.size()) {