blob_handler: fprintf tweak

[src/ipmiblob/blob_handler.cpp:141]: (warning) %d in format string
(no. 1) requires 'int' but the argument type is 'unsigned int'.

Change-Id: I8e695a4656d47abe80396e1929b62b86421e761d
Signed-off-by: Patrick Venture <venture@google.com>
diff --git a/src/ipmiblob/blob_handler.cpp b/src/ipmiblob/blob_handler.cpp
index 2ea927a..74ecd02 100644
--- a/src/ipmiblob/blob_handler.cpp
+++ b/src/ipmiblob/blob_handler.cpp
@@ -138,7 +138,7 @@
         return 0;
     }
 
-    std::fprintf(stderr, "BLOB Count: %d\n", count);
+    std::fprintf(stderr, "BLOB Count: %u\n", count);
     return count;
 }