Do query voice calls until required dbus interface is available
Do query voice calls until required dbus interface is available

MCE wrongly assumes that org.ofono.VoiceCallManager interface is
available immediately after ofono claims org.ofono dbus name on
startup. Apart from spamming the journal with warnings due to this,
it also means mce will not query the voice call attributes when it
finally would be possible.

Wait for modem object to add org.ofono.VoiceCallManager to Interfaces
property before enumerating current voice calls.

[mce] Do query voice calls until required dbus interface is available. Fixes JB#24719

mlehtima/mce,kimmoli/mce,android-808/mce,kimmoli/mce,android-808/mce,spiiroin/mce,android-808/mce,mlehtima/mce,maikelwever/mce,spiiroin/mce,mikkoharju/mce,mikkoharju/mce,mlehtima/mce,kimmoli/mce,maikelwever/mce,android-808/mce,maikelwever/mce,mikkoharju/mce,spiiroin/mce,maikelwever/mce,spiiroin/mce,kimmoli/mce,mlehtima/mce,mikkoharju/mce