Fix cargo build --features consistency_check and test it in CI

Author: jyn514

.github/workflows/ci.yml

@@ -152,4 +152,4 @@ jobs:
       - uses: actions-rs/cargo@v1
         with:
           command: clippy
-          args: --all-targets --workspace --locked -- -D warnings
+          args: --all-features --all-targets --workspace --locked -- -D warnings

src/index/crates.rs

@@ -41,6 +41,6 @@ impl Crates {
             }
         })?;
 
-        Ok(result?)
+        result
     }
 }

src/utils/consistency/mod.rs

@@ -1,5 +1,6 @@
 use self::diff::{Diff, Diffable};
 use crate::Index;
+use anyhow::Context;
 
 mod data;
 mod db;