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/test/tools_blob_unittest.cpp b/test/tools_blob_unittest.cpp
index a9ec639..4b08854 100644
--- a/test/tools_blob_unittest.cpp
+++ b/test/tools_blob_unittest.cpp
@@ -567,7 +567,7 @@
                 sendPacket(ipmiOEMNetFn, ipmiOEMBlobCmd, ContainerEq(request)))
         .WillOnce(Return(resp));
 
-    blob.deleteBlob("abcd");
+    EXPECT_TRUE(blob.deleteBlob("abcd"));
 }
 
 } // namespace ipmiblob