screen activates when proximity sensor covered + incoming call(or SMS)

[TarotChen]

current build number: 334
device name: krillin
channel: ubuntu-touch/rc-proposed/bq-aquaris.en
last update: 2016-05-13 01:22:19
version version: 334
version ubuntu: 20160513
version device: 20160329-a9bacdb
version custom: 20160505-975-38-9

Steps:
1. Phone is flashed with a sim inserted and a secondary device to call it from
2. Cover the proximity sensor (normally located on the front edge around the camera) with the device suspend
3. Trigger an incoming call from a secondary device

Actual result:
Screen activates and displays the OSD

Expected result:
Device rings and vibrates but screen stays blank