QtSensors changelog updated for Qt 5.4.

Change-Id: I3e34ba8503f7b4675a6c629ff5baf9370a7cf63c
Reviewed-by: Lorn Potter <lorn.potter@gmail.com>
Merge remote-tracking branch 'origin/5.4.0' into 5.4

Change-Id: I74fd8ea4b5d458706c7269572fa4679e6fd60a57