tools/mesh-cfgclient: Fix SIGSEGV

tools/mesh-cfgclient: Fix SIGSEGV

This patch addresses the following crash:

[mesh-cfgclient]#
Program received signal SIGSEGV, Segmentation fault.
strlen () at ../sysdeps/x86_64/strlen.S:106
106     ../sysdeps/x86_64/strlen.S: No such file or directory.
(gdb) bt
0  strlen () at ../sysdeps/x86_64/strlen.S:106
1  0x00000000004235d6 in l_dbus_interface_method (interface=interface@entry=0x66d900, name=name@entry=0x42bbad "ScanResult", flags=flags@entry=0,
    cb=cb@entry=0x404940 <scan_result_call>, return_sig=return_sig@entry=0x42f7ca "", param_sig=param_sig@entry=0x42bba4 "naya{sv}") at ell/dbus-service.c:320
2  0x000000000040433d in setup_prov_iface (iface=0x66d900) at tools/mesh-cfgclient.c:1695
3  0x00000000004249b1 in _dbus_object_tree_register_interface (tree=0x65b770, interface=interface@entry=0x42baa8 "org.bluez.mesh.Provisioner1",
    setup_func=setup_func@entry=0x404310 <setup_prov_iface>, destroy=destroy@entry=0x0, old_style_properties=old_style_properties@entry=false)
    at ell/dbus-service.c:1385
4  0x000000000041cffa in l_dbus_register_interface (dbus=<optimized out>, interface=interface@entry=0x42baa8 "org.bluez.mesh.Provisioner1",
    setup_func=setup_func@entry=0x404310 <setup_prov_iface>, destroy=destroy@entry=0x0, handle_old_style_properties=handle_old_style_properties@entry=false)
    at ell/dbus.c:1455
5  0x0000000000403f4e in register_app () at tools/mesh-cfgclient.c:1770
6  client_ready (client=<optimized out>, user_data=<optimized out>) at tools/mesh-cfgclient.c:1815
7  0x0000000000425ed2 in get_managed_objects_reply (message=<optimized out>, user_data=0x66ab50) at ell/dbus-client.c:572
8  0x000000000041bc25 in handle_error (message=0x66c0c0, dbus=<optimized out>) at ell/dbus.c:236
9  0x000000000041cdcc in message_read_handler (io=<optimized out>, user_data=0x6653f0) at ell/dbus.c:276
10 0x0000000000418763 in io_callback (fd=<optimized out>, events=1, user_data=0x6664e0) at ell/io.c:126
11 0x000000000041957a in l_main_iterate (timeout=<optimized out>) at ell/main.c:473
12 0x000000000041964c in l_main_run () at ell/main.c:520
13 0x000000000041986b in l_main_run_with_signal (callback=callback@entry=0x4153a0 <l_sig_func>, user_data=user_data@entry=0x0) at ell/main.c:642
14 0x0000000000415471 in mainloop_run_with_signal (func=func@entry=0x4139a0 <signal_callback>, user_data=user_data@entry=0x0) at src/shared/mainloop-ell.c:87
15 0x0000000000414b6f in bt_shell_run () at src/shared/shell.c:1177
16 0x00000000004039ed in main (argc=<optimized out>, argv=<optimized out>) at tools/mesh-cfgclient.c:1999

Change-Id: If3906df5485d4f2276a51db1c283b5865d626139
Signed-off-by: Anupam Roy <anupam.r@samsung.com>