This app fix the Lollipop vibration issue for Nexus 5 and others phones when is present a flip cover:
When phone is in vibrate and Quick Cover is closed, I feel only one-two seconds vibrate, next phone still ringing, but it is silent (doesn't vibrate). In KitKat that was working.
Some users reported that works also with:
Xperia Z1 (C6903), Moto G, Nexus 6P, Nexus 5X, OnePlus One.