cpuinfoapp: Fix SdBusError exception in match rule

In the match rule looking for new interfaces on cpu objects, the first
thing pulled out of the message is an object_path, not a string. Trying
to read a string first throws an exception caused by
"sd_bus_message_read_basic string: System.Error.ENXIO"

Tested: Added my own interface to the cpu object from within cpuinfoapp
and confirmed that the exception is no longer thrown.

Signed-off-by: Jonathan Doman <jonathan.doman@intel.com>
Change-Id: I72c226c10975159c8505f8da0cac9a7774ecb9e4
1 file changed