test: add unit-test for tools::blob close
test: add unit-test for tools::blob close

Add a unit-test for the host tool blob close command.

Change-Id: I0d8b8af18dabdae8e6bfc3d48ac708b2d4f838ed
Signed-off-by: Patrick Venture <36c53fa43f47f3fd67cb2fc38031827244d18a1f@google.com>

openbmc/phosphor-ipmi-flash