shared/gatt-client: Fix discovering included svcs using invalid range

shared/gatt-client: Fix discovering included svcs using invalid range

[Problem] It discovers included services using invalid handle range 0 ~ 0.
 It causes ATT error response and GATT connection is failed.
[Cause & Measure] When any service is removed over the previous connection,
 pending_svcs queue is not empty because it is used to identify
 disappeared services. So we need to check more if there are any services
 to be discovered or not.
 This patch checks the service range and if there is no service
 to be discovered, stop the discovery.
[Checking Method] Connect to iOS -> Turn off and on iOS's Bluetooth

Change-Id: I312cba9a53c55ce266d98196e3ba81b236d885e9
Signed-off-by: Seungyoun Ju <sy39.ju@samsung.com>
Signed-off-by: DoHyun Pyun <dh79.pyun@samsung.com>