tools: bugfix: add missing close after failure
tools: bugfix: add missing close after failure

Signed-off-by: Patrick Venture <36c53fa43f47f3fd67cb2fc38031827244d18a1f@google.com>
Change-Id: Id873c41997e2617d1fa3db5767112c23d77c487c

openbmc/phosphor-ipmi-flash