Fix number label in quick contacts recent calls list

Custom number label were not being shown in recent calls list due to
database entry for number type being null instead of a valid integer.

Use InCallApi plugin name as label if available, becauase some
plugins use the label column for strings that are too long to be
considered a label.

Ticket CD-460

Change-Id: Ic10cf4bbc6edea8dc7363f7897756df61385581d