handledata contains a 16bit char handle in the lower bits and
may contains a 16bit descriptor handle in its upper 16 bits.
When doing blob read requests for descriptors the upper 16 bit
may be cut off and the descriptor read turns into a characteristic
read. In turn this switches the internal
state of the service discovery state machine causing an endless loop
between descriptor and characteristic reads.

Change-Id: Ia66f230e8fb018da51c3ce32db936d02a0b195b8
Task-number: QTBUG-47028
Reviewed-by: Timur Pocheptsov <Timur.Pocheptsov@digia.com>