Make advance_days only available with test feature

src/lib.rs

@@ -985,9 +985,9 @@ impl BridgeAuth {
         &self.bridge_table.encbuckets
     }
 
-    //#[cfg(test)]
     // For testing only: manually advance the day by the given number
     // of days
+    #[cfg(feature = "test")]
     pub fn advance_days(&mut self, days: u16) {
         self.time_offset += time::Duration::days(days.into());
     }