flux-broker: ev.c:4392: ev_timer_start: Assertion `("libev: ev_timer_start called with negative timer repeat value", w->repeat >= 0.)' failed.

[garlick]

Problem: flux_timer_watcher_reset() allows illegal values of timer parameters to be set which later cause an assertion in libev.

In this case I repeatedly crashed the broker due to a bug in my code, which felt like excessive punishment for a small crime :-)

Unfortunately there is no way for flux_timer_watcher_reset() to indicate that its values are invalid since it has a void return. Perhaps we could just silently change a negative repeat value to 0. (no repeat). Alternatively we could change the prototype to something that can return an error.