message: fix precision source in sql
diff: @@ -425,8 +425,9 @@ namespace iroha {
  AND precision >= $3
  UNION
  - SELECT 4, value < (2::decimal ^ 256) / 10::decimal^$3
  - FROM new_quantity
  + SELECT 4, value < (2::decimal ^ 256) / (10::decimal ^ precision)
  + FROM new_quantity, asset
  + WHERE asset_id = $2
  ),
  inserted AS
  (
  @@ -814,8 +815,9 @@ namespace iroha {
  FROM new_src_quantity
  UNION
  - SELECT 7, value < (2::decimal ^ 256) / 10::decimal^$5
  - FROM new_dest_quantity
  + SELECT 7, value < (2::decimal ^ 256) / (10::decimal ^ precision)
  + FROM new_dest_quantity, asset
  + WHERE asset_id = $4
  ),
  insert_src AS
  (
  