presence: Tach input to double

It was found that after the Value property on the Sensor.Value interface
was changed to be of double type, the tach input failed to get converted
correctly from double to int64 type when the property changed. Need to
set the tach input to be of double type explicitly.

Tested:
    Tach input values correctly read from dbus signal

Change-Id: Ia12697e12b4003c62868f1fb97576df03c46c53f
Signed-off-by: Matthew Barth <msbarth@us.ibm.com>
2 files changed