ASAGW-8 - Some mandatory fields are not initialised in AboutPropertyStoreImpl of GatewayAgent Manager App
Added initialisations of Manufacturer, ModeulNumber, SoftwareVersion and Description fields

Change-Id: Ibd9561cb98a7460d3751a57fe84fb7e1a9168705
Signed-off-by: Eyal Ilsar <eyali@qce.qualcomm.com>