upgrade various Rust dependencies

This stops using parking_lot entirely. Since Rust 1.62, the std
implementations on Linux are direct futexes, not the boxed pthread
mutexes they used to be. No real reason to use parking_lot anymore, so
shed this dependency.

server/db/upgrade/mod.rs

@@ -126,7 +126,7 @@ struct UuidPath([u8; 37]);
 impl UuidPath {
     pub(crate) fn from(uuid: Uuid) -> Self {
         let mut buf = [0u8; 37];
-        write!(&mut buf[..36], "{}", uuid.to_hyphenated_ref())
+        write!(&mut buf[..36], "{}", uuid.as_hyphenated())
             .expect("can't format uuid to pathname buf");
         UuidPath(buf)
     }

server/db/upgrade/v1_to_v2.rs

@@ -323,7 +323,7 @@ fn verify_dir_contents(
             Ok(u) => u,
             Err(_) => bail!("unexpected file {:?} in {:?}", f, sample_file_path),
         };
-        if s != uuid.to_hyphenated_ref().to_string() {
+        if s != uuid.as_hyphenated().to_string() {
             // non-canonical form.
             bail!("unexpected file {:?} in {:?}", f, sample_file_path);
         }

server/db/upgrade/v5_to_v6.rs

@@ -108,7 +108,7 @@ pub fn run(_args: &super::Args, tx: &rusqlite::Transaction) -> Result<(), Error>
         if avcc.num_of_sequence_parameter_sets() != 1 {
             bail!("Multiple SPSs!");
         }
-        let ctx = avcc.create_context(()).map_err(|e| {
+        let ctx = avcc.create_context().map_err(|e| {
             format_err!(
                 "Can't load SPS+PPS for video_sample_entry_id {}: {:?}",
                 id,