Fix clippy

[lxfind]

No description provided.

[huitseeker]

While you're here, the same job at https://github.com/MystenLabs/sui/runs/8296329081?check_suite_focus=true is pointing out the following unneeded dependencies:

unused dependencies:
`sui v0.9.0 (/home/runner/work/sui/sui/crates/sui)`
└─── dependencies
     └─── "sui-simulator"
`sui-config v0.0.0 (/home/runner/work/sui/sui/crates/sui-config)`
└─── dependencies
     └─── "sui-simulator"
`sui-macros v0.7.0 (/home/runner/work/sui/sui/crates/sui-macros)`
└─── dependencies
     └─── "darling"
`sui-swarm v0.0.0 (/home/runner/work/sui/sui/crates/sui-swarm)`
└─── dependencies
     └─── "sui-simulator"
Note: These dependencies might be used by other targets.
      To find dependencies that are not used by any target, enable `--all-targets`.
Note: They might be false-positive.
      For example, `cargo-udeps` cannot detect usage of crates that are only used in doc-tests.
      To ignore some dependencies, write `package.metadata.cargo-udeps.ignore` in Cargo.toml.
Error: Process completed with exit code 1.

For your consideration.

[lxfind]

@mystenmark Can you take a look at the udeps failure in the nightly build? It seems that I cannot remove those deps otherwise simtest would fail.