Don't throw exception if FRU inventory path is not present

Currently if 'fruPath' refers to an inventory path that is not present
in the system, 'isFruPresent' function will throw an exception which
will be unhandled.
Replace 'getDbusProperty' call with its yelding version and handle all
possible cases.

Signed-off-by: Konstantin Aladyshev <aladyshev22@gmail.com>
Change-Id: I4ef901572024b37b777536ebef70d9c3422fb3ed
1 file changed