Revert "[client] po: Consistent Japanese notations."

This reverts commit 6ecfc261617f777f6ee02bed86c32f7b2e9ff0e9.

I wrongly merged this pull request. So I once revert it.

I think we should have more discussion about this topic because Zabbix,
one of the major monitoring systems Hatohol supports, uses last "-".
So we have to decide whether to use the same expressions (words) or our own.