node/log: Define syslog identifier

The argument passed to `fn logger` would only be used as a fallback.
Make it required to pass an identifier, as this is a good practice.

crates/radicle-node/src/main.rs

@@ -338,7 +338,8 @@ fn initialize_logging(options: &LogOptions) -> Result<(), Box<dyn std::error::Er
                     return Err(Box::new(JournalError::NotConnected));
                 }
 
-                logger::<&str, &str, _>("radicle-node".to_string(), []).map_err(Box::new)?
+                const SYSLOG_IDENTIFIER: &str = "radicle-node";
+                logger::<&str, &str, _>(SYSLOG_IDENTIFIER.to_string(), []).map_err(Box::new)?
             }
             Logger::Radicle => Box::new(radicle::logger::Logger::new(level)),
         }

crates/radicle-systemd/src/journal.rs

@@ -1,11 +1,8 @@
-use systemd_journal_logger::{connected_to_journal, current_exe_identifier, JournalLog};
+use systemd_journal_logger::{connected_to_journal, JournalLog};
 
 /// If the current process is directly connected to the systemd journal,
 /// return a logger that will write to it.
-pub fn logger<K, V, I>(
+pub fn logger<K, V, I>(identifier: String, extra_fields: I) -> std::io::Result<Box<dyn log::Log>>
-    default_identifier: String,
-    extra_fields: I,
-) -> std::io::Result<Box<dyn log::Log>>
 where
     I: IntoIterator<Item = (K, V)>,
     K: AsRef<str>,
@@ -13,7 +10,7 @@ where
 {
     Ok(Box::new(
         JournalLog::new()?
-            .with_syslog_identifier(current_exe_identifier().unwrap_or(default_identifier))
+            .with_syslog_identifier(identifier)
             .with_extra_fields(extra_fields),
     ))
 }