Resolve our migration record during initRepos.

Otherwise, if a data migration is registered and run after the initialization
process, we'll end up warning that this record has not yet been initialized.

In theory, you should register your data migrations prior to calling initRepos,
but I don't want to be too draconian about that. Unlike schema migrations, you
*could* conceivably mean to start your app up and let it run before running
data migrations.

src/main/java/com/samskivert/depot/PersistenceContext.java

@@ -30,11 +30,12 @@ import com.samskivert.depot.CacheAdapter.CachedValue;
 import com.samskivert.depot.annotation.TableGenerator;
 import com.samskivert.depot.impl.DepotMarshaller;
 import com.samskivert.depot.impl.DepotMetaData;
+import com.samskivert.depot.impl.DepotMigrationHistoryRecord;
 import com.samskivert.depot.impl.DepotTypes;
+import com.samskivert.depot.impl.Fetcher;
 import com.samskivert.depot.impl.KeyCacheKey;
 import com.samskivert.depot.impl.Modifier;
 import com.samskivert.depot.impl.Operation;
-import com.samskivert.depot.impl.Fetcher;
 import com.samskivert.depot.impl.SQLBuilder;
 
 import static com.samskivert.depot.Log.log;
@@ -530,6 +531,8 @@ public class PersistenceContext
     public void initializeRepositories (boolean warnOnLazyInit)
         throws DatabaseException
     {
+        // resolve our internal tracking table
+        getMarshaller(DepotMigrationHistoryRecord.class);
         // resolve all persistent records and trigger all schema migrations
         for (DepotRepository repo : _repositories) {
             repo.resolveRecords();