Add supportsCheckpoint

This returns true if any entries in the fstab have checkpoint=
set.

Test: Call vdc checkpoint supportsCheckpoint. Should return 1
      iff an fstab entry has checkpoint=fs or checkpoint=block set
Bug: 111020314

Change-Id: Ic79bc96ded4da6605f73992dcff542e7cb50d705
diff --git a/VoldNativeService.h b/VoldNativeService.h
index 161acb8..7db3e5c 100644
--- a/VoldNativeService.h
+++ b/VoldNativeService.h
@@ -129,6 +129,7 @@
     binder::Status restoreCheckpoint(const std::string& mountPoint);
     binder::Status markBootAttempt();
     binder::Status abortChanges();
+    binder::Status supportsCheckpoint(bool* _aidl_return);
 };
 
 }  // namespace vold