Don't call block checkpoint functions above dm-default-key

Bug: 156225476
Test: Build for f2fs and ext4 device, make sure checkpoints roll back
and commit

Change-Id: Ic15fadc67d306463dd0b554f679306d8f9081451
diff --git a/MetadataCrypt.cpp b/MetadataCrypt.cpp
index 7891bee..bf0220e 100644
--- a/MetadataCrypt.cpp
+++ b/MetadataCrypt.cpp
@@ -103,7 +103,7 @@
     }
     auto mount_rc = fs_mgr_do_mount(&fstab_default, const_cast<char*>(mount_point),
                                     const_cast<char*>(blk_device), nullptr,
-                                    android::vold::cp_needsCheckpoint());
+                                    android::vold::cp_needsCheckpoint(), true);
     if (setexeccon(nullptr)) {
         PLOG(ERROR) << "Failed to clear setexeccon";
         return false;