Fix showing wrong UUID, remove unused library

[UntriexTv]

In case of invalid UUID agent showed:

WARN  keylime_agent::config > Misformatted UUID: invalid-uuid-0909
INFO  keylime_agent::config > Using generated UUID: invalid-uuid-0909

and warning while compiling:

warning: unused import: `std::io::prelude`
    --> keylime/src/tpm.rs:1816:9
     |
1816 |     use std::io::prelude::*;
     |         ^^^^^^^^^^^^^^^^
     |
     = note: `#[warn(unused_imports)]` on by default

[THS-on]

@UntriexTv thanks for the fix. Can you add a signoff line in the commit? I think you can't drop the import because the tests are no longer building.

[THS-on]

@UntriexTv can you also squash your commits together. Once that is done and rest of the test pass this LGTM.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 59.63%. Comparing base (2f7b3ad) to head (bf49b4f).
Report is 57 commits behind head on master.

Additional details and impacted files

Flag	Coverage Δ
e2e-testsuite	59.63% <100.00%> (+2.04%)	⬆️
upstream-unit-tests	59.63% <100.00%> (+8.62%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
keylime-agent/src/config.rs	74.11% <100.00%> (-13.39%)	⬇️

... and 9 files with indirect coverage changes

[ansasaki]

@UntriexTv thank you for your contribution!

Could you please squash the commits into a single commit? I'd like to avoid adding commits that add a change just to revert it back in the following commit.

[UntriexTv]

Sorry for late reply, didn't have much time to check github in past days.

[ansasaki]

LGTM!