charts: ensure first update always samples

vmon steps on this edge case, in vwm it was largely benign
since nothing ever happens immediately at vwm startup.

But in vmon you do things monitor commands which might
immediately send SIGUSR1 to vmon for .png snapshots, producing an
empty .png because the first update didn't sample because the
time delta hadn't passed.

This change just maintains a "primed" charts flag to ensure the
initial charts update always samples.  This way if got_sigusr1 is
already set on the first iteration, at least the first charts
update will have sampled and composited *something*.

0 files changed, 0 insertions, 0 deletions