Update toolchain to nightly-2021-09-18

This seemingly innoucous update required several changes due to changes
in how the compiler interprets dead code.

* A few variables were renamed _x where it looked like x might be used
  in upcoming PRs. YAGNI maybe, but I gave the benefit of the doubt in
this cases.
* Some crates that had LOADS of dead code (ffi crate I'm looking at
  you), I just changed the `deny(dead_code)` to `warn(dead_code)`
* And in some places, I just nuked the dead code, which tidied up some
  heavy code in the wallet in particular. Since the tests pass, I
presume this is fine and there isn't a weird new compioler bug that is
missing where the code is needed.

Update hardcoded toolchain specs

..and update circleCI config

PRevent multiplexing in docker CI

.circleci/config.yml

@@ -1,7 +1,7 @@
 version: 2.1
 
 defaults:
-  rust_image: &rust_image quay.io/tarilabs/rust_tari-build-with-deps:nightly-2021-08-18
+  rust_image: &rust_image quay.io/tarilabs/rust_tari-build-with-deps:nightly-2021-09-18
 
 commands:
   test:
@@ -76,13 +76,13 @@ commands:
       - run:
           name: Cargo fmt
           command: |
-            TOOLCHAIN=$(cat rust-toolchain)
+            TOOLCHAIN=$(awk '/channel = /{print $NF}' rust-toolchain.toml)
             rustup component add --toolchain $TOOLCHAIN rustfmt
             cargo fmt --all -- --check
       - run:
           name: Run clippy (main source)
           command: |
-            TOOLCHAIN=$(cat rust-toolchain)
+            TOOLCHAIN=$(awk '/channel = /{print $NF}' rust-toolchain.toml)
             rustup component add --toolchain $TOOLCHAIN clippy
             cargo clippy -- -D warnings -W clippy::cognitive_complexity
       - run:

.github/workflows/audit.yml

@@ -7,7 +7,7 @@ jobs:
   security_audit:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v1
+      - uses: actions/checkout@v2
       - uses: actions-rs/audit-check@v1
         with:
           token: ${{ secrets.GITHUB_TOKEN }}

.github/workflows/base_node_binaries.yml

@@ -61,7 +61,7 @@ jobs:
       - name: Setup Rust toolchain
         uses: actions-rs/toolchain@v1
         with:
-          toolchain: nightly-2021-08-18
+          toolchain: nightly-2021-09-18
           components: rustfmt
           override: true
 

.github/workflows/ci.yml

@@ -8,8 +8,11 @@ on:
     types: [opened, synchronize, reopened]
 
 name: CI
+
 env:
-  toolchain: nightly-2021-08-18
+  CARGO_HTTP_MULTIPLEXING: false
+  toolchain: nightly-2021-09-18
+
 jobs:
   clippy:
     name: clippy

.github/workflows/libwallet.yml

@@ -48,13 +48,13 @@ jobs:
       - uses: actions/checkout@v2
       - uses: actions-rs/toolchain@v1
         with:
-          toolchain: nightly-2021-08-18
+          toolchain: nightly-2021-09-18
           target: aarch64-apple-ios
           components: rustfmt
           override: true
       - uses: actions-rs/toolchain@v1
         with:
-          toolchain: nightly-2021-08-18
+          toolchain: nightly-2021-09-18
           target: x86_64-apple-ios
           components: rustfmt
           override: true