blob_handler: fprintf tweak
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 <36c53fa43f47f3fd67cb2fc38031827244d18a1f@google.com>

openbmc/ipmi-blob-tool