Minor fixes (#2038)

Fixes a couple of low hanging fruits.

- Fixes #2037 
- `validators-dir` and `secrets-dir` flags don't really need to depend upon each other
- Fixes #2006 and Fixes #1995

beacon_node/beacon_chain/src/eth1_chain.rs

@@ -813,7 +813,7 @@ mod test {
                         .write()
                         .cache
                         .insert_log(log.clone())
-                        .expect("should insert log")
+                        .expect("should insert log");
                 })
                 .collect();