[review] error type cleanup variant

Author: zeeshanlakhani

rdb/src/error.rs

@@ -15,9 +15,6 @@ pub enum Error {
     #[error("serialization error {0}")]
     Serialization(#[from] serde_json::Error),
 
-    #[error("io error {0}")]
-    Io(#[from] std::io::Error),
-
     #[error("db key error {0}")]
     DbKey(String),