New buckets for 0.6.0: small changes

- Fix bucket delete

- fix merge of bucket creation date

- Replace deletable with option in aliases
    Rationale: if two aliases point to conflicting bucket, resolving
    by making an arbitrary choice risks making data accessible when it
    shouldn't be. We'd rather resolve to deleting the alias until
    someone puts it back.

src/util/data.rs

@@ -5,7 +5,7 @@ use serde::{Deserialize, Deserializer, Serialize, Serializer};
 use std::fmt;
 
 /// An array of 32 bytes
-#[derive(Default, PartialOrd, Ord, Clone, Hash, PartialEq, Copy)]
+#[derive(Default, Clone, Hash, PartialEq, Eq, PartialOrd, Ord, Copy)]
 pub struct FixedBytes32([u8; 32]);
 
 impl From<[u8; 32]> for FixedBytes32 {
@@ -20,8 +20,6 @@ impl std::convert::AsRef<[u8]> for FixedBytes32 {
 	}
 }
 
-impl Eq for FixedBytes32 {}
-
 impl fmt::Debug for FixedBytes32 {
 	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 		write!(f, "{}…", hex::encode(&self.0[..8]))