Set the signal monitor deadline based on the recording end time.

Previously, it used the scheduled (i.e.e guide) end time.  That caused
immediate recording failures when the program was started or restarted
during the end-late period.

(cherry picked from commit 752cbb5e818b58321256c810a4aa8534c13fb339)
Revert efea2ba1, signal monitor deadline tweak, if favor of a better,
future fix.

(cherry picked from commit aefe1e3c89a410178145f7b7a788b041841c6ffa)