Fix warnings in preparation for Rust 1.54.0

This CL fixes several new warnings generated by rustc 1.54.0.

Bug: 194812675
Test: m rust
Change-Id: I3076313ea51c6f4e74029ad9fb45d6f0b6dea460
diff --git a/keystore2/src/legacy_migrator.rs b/keystore2/src/legacy_migrator.rs
index f92fd45..65f4b0b 100644
--- a/keystore2/src/legacy_migrator.rs
+++ b/keystore2/src/legacy_migrator.rs
@@ -567,7 +567,7 @@
 
         if let Some(super_key) = self
             .legacy_loader
-            .load_super_key(user_id, &pw)
+            .load_super_key(user_id, pw)
             .context("In check_and_migrate_super_key: Trying to load legacy super key.")?
         {
             let (blob, blob_metadata) =
@@ -724,8 +724,8 @@
 
     fn deref(&self) -> &Self::Target {
         match self {
-            Self::Vec(v) => &v,
-            Self::ZVec(v) => &v,
+            Self::Vec(v) => v,
+            Self::ZVec(v) => v,
         }
     }
 }