Remove explicit date in influxdb writes

Created by: joshmue

The busybox date yields different results than the GNU coreutils date. Specifically, it does not seem to expand %N to nanoseconds, which seems to cause incorrect time mappings inside of telegraf.

Omitting the date altogether makes telegraf (in the version that I tested) adding it automatically, which should be fine for this use case.

CC @berendt @garloff

Signed-off-by: Joshua Mühlfort muehlfort@gonicus.de