blob_handler: Have delete return a status

A user of this library would like to know if the delete operation
succeeds or fails.

Change-Id: Ida5890be9dad214854527c8afffd05bffc7e5e2a
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/src/ipmiblob/blob_handler.hpp b/src/ipmiblob/blob_handler.hpp
index 33634fd..a9e6ef4 100644
--- a/src/ipmiblob/blob_handler.hpp
+++ b/src/ipmiblob/blob_handler.hpp
@@ -82,7 +82,7 @@
 
     void closeBlob(std::uint16_t session) override;
 
-    void deleteBlob(const std::string& id) override;
+    bool deleteBlob(const std::string& id) override;
 
     /**
      * @throws BlobException.