attrib/gatt: Fix for search services
attrib/gatt: Fix for search services

This patch adds means to reuse ATT request id for GATT operations
which might need more then one ATT request for complete GATT operation.
E.g discover primary\included services and discover
characteristics/descriptors

This is needed for the user of gattib, to make sure that ATT request id he
holds is valid during whole GATT operation.

So far, it could happen that gattrib did additional ATT request without
user knowledge which leads to situation that user had outdated ATT
request id.

Note that request id is used by the user for canceling request.

pstglia/external-bluetooth-bluez,mapfau/bluez,pkarasev3/bluez,silent-snowman/bluez,pkarasev3/bluez,mapfau/bluez,pkarasev3/bluez,pstglia/external-bluetooth-bluez,pstglia/external-bluetooth-bluez,silent-snowman/bluez,ComputeCycles/bluez,silent-snowman/bluez,silent-snowman/bluez,ComputeCycles/bluez,mapfau/bluez,pstglia/external-bluetooth-bluez,ComputeCycles/bluez,pkarasev3/bluez,ComputeCycles/bluez,mapfau/bluez