Fix for #155

[infraweavers]

Previously the value of $stats{timet} would be initialised based on the last time that omd restart pnp_gearman_worker was executed, this means that the longer that OMD runs, each new instance of the worker that's created starts off with a "broken" snapshot of their stats. By initialising it to 0 and skipping that save, we throw away the first-time stats (which are empty anyway) and then save from then onward.

NB I think the format of this patch is correct, however I don't have a build environment for the whole of OMD built so I've had to guess it a little.