Fix sqlite purgepurgeMapTilesStatement

Author: TBlueF

BlueMapCore/src/main/java/de/bluecolored/bluemap/core/storage/sql/commandset/SqliteCommandSet.java

@@ -196,7 +196,7 @@ public String purgeMapTilesStatement() {
         DELETE
         FROM bluemap_map_tile
         WHERE ROWID IN (
-         SELECT ROWID
+         SELECT t.ROWID
          FROM bluemap_map_tile t
           INNER JOIN bluemap_map m
            ON t.map = m.id