[keyserver] convert secondary migration block from do while to regula…

…r while loop

Summary: The `do-while` ensures an unnecessary 5 second sleep time. Converting this to a `while` loop ensures this only happens if necessary

Test Plan: flow check

Reviewers: ashoat

Reviewed By: ashoat

Subscribers: tomek

Differential Revision: https://phab.comm.dev/D13273

keyserver/src/keyserver.js

@@ -238,12 +238,12 @@ void (async () => {
     server.listen(parseInt(process.env.PORT, 10) || 3000, listenAddress);
 
     if (isSecondaryNode) {
-      let dbVersion;
-      do {
+      let dbVersion = await fetchDBVersion();
+      while (dbVersion < latestWrapInTransactionAndBlockRequestsVersion) {
         await sleep(5000);
 
         dbVersion = await fetchDBVersion();
-      } while (dbVersion < latestWrapInTransactionAndBlockRequestsVersion);
+      }
     }
 
     // Note - the order of router declarations matters. On prod we have