Fix compile warnings

[boundless-forest]

warning: using `.borrow()` on a double reference, which returns `&(&str, &xcm::v3::MultiLocation)` instead of borrowing the inner type
   --> runtime/common/src/xcm_configs.rs:128:55
    |
128 |         let hash: [u8; 32] = ("multiloc", location.borrow()).borrow().using_encoded(blake2_256);
    |                                                             ^^^^^^^^^
    |
    = note: `#[warn(suspicious_double_ref_op)]` on by default

warning: `darwinia-common-runtime` (lib) generated 1 warning
    Checking darwinia v6.3.4 (/home/bear/coding/rust-space/darwinia/node)
    Finished release [optimized] target(s) in 3.00s

---

warning: function `ensure_dev` is never used
   --> node/src/command.rs:915:4
    |
915 | fn ensure_dev(spec: &dyn IdentifyVariant) -> Result<()> {
    |    ^^^^^^^^^^
    |
    = note: `#[warn(dead_code)]` on by default

warning: `darwinia` (bin "darwinia") generated 1 warning
    Finished release [optimized] target(s) in 10m 42s

[boundless-forest]

warning: /home/bear/coding/rust-space/darwinia/runtime/crab/Cargo.toml: unused manifest key: dependencies.codec.package
warning: /home/bear/coding/rust-space/darwinia/pallet/message-gadget/Cargo.toml: unused manifest key: dependencies.codec.package
warning: /home/bear/coding/rust-space/darwinia/runtime/darwinia/Cargo.toml: unused manifest key: dependencies.codec.package
warning: /home/bear/coding/rust-space/darwinia/runtime/pangoro/Cargo.toml: unused manifest key: dependencies.codec.package
warning: /home/bear/coding/rust-space/darwinia/pallet/account-migration/Cargo.toml: unused manifest key: dependencies.codec.package
warning: /home/bear/coding/rust-space/darwinia/pallet/staking/traits/Cargo.toml: unused manifest key: dependencies.codec.package
warning: /home/bear/coding/rust-space/darwinia/precompile/assets/Cargo.toml: unused manifest key: dev-dependencies.codec.package
warning: /home/bear/coding/rust-space/darwinia/pallet/staking/Cargo.toml: unused manifest key: dependencies.codec.package
warning: /home/bear/coding/rust-space/darwinia/runtime/common/Cargo.toml: unused manifest key: dependencies.codec.package
warning: /home/bear/coding/rust-space/darwinia/pallet/ecdsa-authority/Cargo.toml: unused manifest key: dependencies.codec.package
warning: /home/bear/coding/rust-space/darwinia/pallet/message-transact/Cargo.toml: unused manifest key: dependencies.codec.package
warning: /home/bear/coding/rust-space/darwinia/precompile/deposit/Cargo.toml: unused manifest key: dev-dependencies.codec.package
warning: /home/bear/coding/rust-space/darwinia/precompile/staking/Cargo.toml: unused manifest key: dev-dependencies.codec.package
warning: /home/bear/coding/rust-space/darwinia/precompile/state-storage/Cargo.toml: unused manifest key: dev-dependencies.codec.package
warning: /home/bear/coding/rust-space/darwinia/node/Cargo.toml: unused manifest key: dependencies.codec.package
warning: /home/bear/coding/rust-space/darwinia/runtime/pangolin/Cargo.toml: unused manifest key: dependencies.codec.package
warning: /home/bear/coding/rust-space/darwinia/pallet/deposit/Cargo.toml: unused manifest key: dependencies.codec.package

No idea what these warning means yet. Leave it alone for now.