Make Rain of Fire work like Berserker Rage

[Chronosplit]

I mean as in the way it shuts off while sustained.

Rain of Fire currently shuts off on rest and run, which is great. However I still cannot keep this sustained at all times because it's missing one critical component: the ability to keep off when normally exploring. The effect on a Demonologist's Vim is not unlike a Berserker's health if Rage was kept on during this time, so it's not entirely useful at that point.