build: Fix beta clippy issue (derive_partial_eq_without_eq)

warning: you are deriving `PartialEq` and can implement `Eq`
  --> vmm/src/serial_manager.rs:59:30
   |
59 | #[derive(Debug, Clone, Copy, PartialEq)]
   |                              ^^^^^^^^^ help: consider deriving `Eq` as well: `PartialEq, Eq`
   |
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#derive_partial_eq_without_eq

Signed-off-by: Rob Bradford <robert.bradford@intel.com>

rate_limiter/src/lib.rs

@@ -91,7 +91,7 @@ pub enum BucketReduction {
 
 /// TokenBucket provides a lower level interface to rate limiting with a
 /// configurable capacity, refill-rate and initial burst.
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, PartialEq, Eq)]
 pub struct TokenBucket {
     // Bucket defining traits.
     size: u64,