Remove unused debugging feature

Cargo.toml

@@ -58,4 +58,3 @@ rustc_tools_util = { version = "0.2.0", path = "rustc_tools_util"}
 
 [features]
 deny-warnings = []
-debugging = []

appveyor.yml

@@ -37,10 +37,10 @@ install:
 build: false
 
 build_script:
-  - cargo build --features debugging
+  - cargo build --features deny-warnings
 
 test_script:
-  - cargo test --features debugging
+  - cargo test --features deny-warnings
 
 notifications:
   - provider: Email

ci/base-tests.sh

@@ -12,8 +12,8 @@ if [[ "$TRAVIS_OS_NAME" == "linux" ]]; then
   remark -f ./*.md -f doc/*.md > /dev/null
 fi
 # build clippy in debug mode and run tests
-cargo build --features "debugging deny-warnings"
-cargo test --features "debugging deny-warnings"
+cargo build --features deny-warnings
+cargo test --features deny-warnings
 
 (cd clippy_lints && cargo test)
 (cd rustc_tools_util && cargo test)

clippy_lints/Cargo.toml

@@ -35,4 +35,4 @@ semver = "0.9.0"
 url = { version =  "2.1.0", features = ["serde"] }
 
 [features]
-debugging = []
+deny-warnings = []