Bug 1245925 - Revert cset 2ae6e19e2caf now that a proper fix has landed. r=me

b2g/app/b2g.js

@@ -1015,7 +1015,6 @@ pref("security.exthelperapp.disable_background_handling", true);
 // Inactivity time in milliseconds after which we shut down the OS.File worker.
 pref("osfile.reset_worker_delay", 5000);
 
-pref("apz.displayport_expiry_ms", 0);
 // APZ physics settings, tuned by UX designers
 pref("apz.axis_lock.mode", 2); // Use "sticky" axis locking
 pref("apz.fling_curve_function_x1", "0.41");