Fix db-migration-period default (#4441)

* Fix db-migration-period default

* Fix version regex

beacon_node/src/cli.rs

@@ -697,7 +697,7 @@ pub fn cli_app<'a, 'b>() -> App<'a, 'b> {
                 .help("Specifies the number of epochs to wait between applying each finalization \
                        migration to the database. Applying migrations less frequently can lead to \
                        less total disk writes.")
-                .default_value("4")
+                .default_value("1")
                 .takes_value(true)
         )
         .arg(

common/lighthouse_version/src/lib.rs

@@ -37,9 +37,8 @@ mod test {
 
     #[test]
     fn version_formatting() {
-        let re =
-            Regex::new(r"^Lighthouse/v[0-9]+\.[0-9]+\.[0-9]+(-tree.[0-9])?(-[[:xdigit:]]{7})?\+?$")
-                .unwrap();
+        let re = Regex::new(r"^Lighthouse/v[0-9]+\.[0-9]+\.[0-9]+(-exp)?(-[[:xdigit:]]{7})?\+?$")
+            .unwrap();
         assert!(
             re.is_match(VERSION),
             "version doesn't match regex: {}",