Fix issues with testnet dir and update docs (#992)

eth2/utils/eth2_config/src/lib.rs

@@ -1,7 +1,4 @@
 use serde_derive::{Deserialize, Serialize};
-use std::fs::File;
-use std::io::prelude::*;
-use std::path::PathBuf;
 use types::ChainSpec;
 
 /// The core configuration of a Lighthouse beacon node.
@@ -44,45 +41,6 @@ impl Eth2Config {
     }
 }
 
-/// Write a configuration to file.
-pub fn write_to_file<T>(path: PathBuf, config: &T) -> Result<(), String>
-where
-    T: Default + serde::de::DeserializeOwned + serde::Serialize,
-{
-    if let Ok(mut file) = File::create(path.clone()) {
-        let toml_encoded = toml::to_string(&config).map_err(|e| {
-            format!(
-                "Failed to write configuration to {:?}. Error: {:?}",
-                path, e
-            )
-        })?;
-        file.write_all(toml_encoded.as_bytes())
-            .unwrap_or_else(|_| panic!("Unable to write to {:?}", path));
-    }
-
-    Ok(())
-}
-
-/// Loads a `ClientConfig` from file. If unable to load from file, generates a default
-/// configuration and saves that as a sample file.
-pub fn read_from_file<T>(path: PathBuf) -> Result<Option<T>, String>
-where
-    T: Default + serde::de::DeserializeOwned + serde::Serialize,
-{
-    if let Ok(mut file) = File::open(path.clone()) {
-        let mut contents = String::new();
-        file.read_to_string(&mut contents)
-            .map_err(|e| format!("Unable to read {:?}. Error: {:?}", path, e))?;
-
-        let config = toml::from_str(&contents)
-            .map_err(|e| format!("Unable to parse {:?}: {:?}", path, e))?;
-
-        Ok(Some(config))
-    } else {
-        Ok(None)
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;