timeval: Always log true poll interval instead of rounding off.
This code triggers when a trip through the process's main loop takes much
longer than expected. The code for calculating the expected time rounds
down to a maximum of 10000 ms to avoid overflow. But there is no reason
that the correct time should not be displayed in the log message, and
furthermore displaying the correct time may help tracking down the
underlying issue, since it lets the administrator find out exactly when
the trip through the main loop started. So this commit displays the exact
time without rounding down.