Revert "lib/data_store.rb: resolve 'from_data': undefined method each' for nil:NilClass'"

This reverts commit 5e2a369.

It requires to call MResultRootTableSet.create_tables_layout properly, and
no need for this explicit fix of missing layout.yaml.

Signed-off-by: Philip Li <philip.li@intel.com>

Author: rli9

lib/data_store.rb

@@ -74,7 +74,7 @@ def load
       begin
         elayout = load_yaml path(CONFIG_FILE)
       rescue StandardError
-        elayout = { MAPS => [], COMPRESS_MATRIX => nil }
+        elayout = {}
       end
       from_data elayout
     end