InCallUI: fix non-intrusive for RTL

http://jira.omnirom.org/browse/OMNI-522

Change-Id: Ib712ccc2c207e329bdfa4cf64d29f2aeb130f59b
Add incoming call to background (non-intrusive InCall improvement)

Change-Id: Ic681eb85915f4fc4e150b6ead72a8794fd0b3410