tools: blob: implement open blob

Implement the host-side tool's open blob command.

Change-Id: Iee432eae0539015e87969159a3d03761df9f8fb5
Signed-off-by: Patrick Venture <venture@google.com>
diff --git a/tools/blob_handler.hpp b/tools/blob_handler.hpp
index fbc6fcb..bcac0a8 100644
--- a/tools/blob_handler.hpp
+++ b/tools/blob_handler.hpp
@@ -52,6 +52,9 @@
 
     std::vector<std::string> getBlobList() override;
     StatResponse getStat(const std::string& id) override;
+    std::uint16_t
+        openBlob(const std::string& id,
+                 blobs::FirmwareBlobHandler::UpdateFlags handlerFlags) override;
 
   private:
     IpmiInterface* ipmi;