add prerm for debian
add prerm for debian

iantalarico/google-fluentd,GoogleCloudPlatform/google-fluentd,treasure-data/omnibus-td-agent,GoogleCloudPlatform/google-fluentd,treasure-data/omnibus-td-agent,treasure-data/omnibus-td-agent,GoogleCloudPlatform/google-fluentd,iantalarico/google-fluentd,iantalarico/google-fluentd