gobex: tools: Fix test-client to use ERTM while on packet mode
gobex: tools: Fix test-client to use ERTM while on packet mode

OBEX should only be used with ERTM over L2CAP and set MTU properly

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