Remove an unnecessary else

The if block above always returns, acting as a guard, so there's no
reason for an else here.

src/bytes_mut.rs

@@ -726,11 +726,11 @@ impl BytesMut {
                 }
 
                 return;
-            } else {
-                new_cap = cmp::max(new_cap, original_capacity);
             }
         }
 
+        new_cap = cmp::max(new_cap, original_capacity);
+
         // Create a new vector to store the data
         let mut v = ManuallyDrop::new(Vec::with_capacity(new_cap));