[WIP] This commit is WIP commit.

This commit refs #94.
Run `td-agent` as a `root` user.

In order to enable `td-agent` to read the logs that cannot be read by td-agent user,
run `td-agent` as a `root` user.

This commit refs #94.
Merge pull request #94 from kazu634/id/94

[td-agent] 実行ユーザーをrootにする