ii: log very unexpected decode failure as warning
ii: log very unexpected decode failure as warning

kenhys/groonga,naoa/groonga,komainu8/groonga,kenhys/groonga,groonga/groonga,kenhys/groonga,komainu8/groonga,kenhys/groonga,komainu8/groonga,komainu8/groonga,kenhys/groonga,komainu8/groonga,groonga/groonga,groonga/groonga,komainu8/groonga,naoa/groonga,groonga/groonga,groonga/groonga,groonga/groonga,kenhys/groonga,komainu8/groonga,komainu8/groonga,kenhys/groonga,naoa/groonga,groonga/groonga,naoa/groonga,groonga/groonga,naoa/groonga,naoa/groonga,naoa/groonga,naoa/groonga,kenhys/groonga