Call InitPartitionMetadata when resuming an update.

BootControlAndroid::InitPartitionMetadata() should always be called when
starting / resuming an update that uses dynamic partitions. This allows
updating the metadata for the target slot, as well as setting up the
internal state for accessing the dynamic partitions in the target slot.

Bug: 122097567
Test: Run update_engine_unittests on taimen and blueline.
Test: Apply a payload that uses dynamic partitions. Reboot before it
      finishes, then resume the update.
Change-Id: I1353f7460a61c0183654b6349689beaa9bf12129
diff --git a/boot_control_chromeos.cc b/boot_control_chromeos.cc
index a82efc7..4fa1268 100644
--- a/boot_control_chromeos.cc
+++ b/boot_control_chromeos.cc
@@ -303,7 +303,9 @@
 }
 
 bool BootControlChromeOS::InitPartitionMetadata(
-    Slot slot, const PartitionMetadata& partition_metadata) {
+    Slot slot,
+    const PartitionMetadata& partition_metadata,
+    bool update_metadata) {
   return true;
 }