Fixed memory related issues reported by valgrind.

Fixed memory related issues reported by valgrind.

==1191== Invalid read of size 4
==1191==    at 0x4AF034C: g_variant_unref (in /usr/lib/libglib-2.0.so.0.5200.2)
==1191==    by 0x49677AF: ??? (in /usr/lib/libgio-2.0.so.0.5200.2)
==1191==    by 0x4A232F3: g_object_unref (in /usr/lib/libgobject-2.0.so.0.5200.2)
==1191==    by 0x4973A33: ??? (in /usr/lib/libgio-2.0.so.0.5200.2)
==1191==    by 0x497555B: ??? (in /usr/lib/libgio-2.0.so.0.5200.2)
==1191==    by 0x4928777: ??? (in /usr/lib/libgio-2.0.so.0.5200.2)
==1191==    by 0x49287AB: ??? (in /usr/lib/libgio-2.0.so.0.5200.2)
==1191==    by 0x4AB08E7: g_main_context_dispatch (in /usr/lib/libglib-2.0.so.0.5200.2)
==1191==    by 0x4AB0C77: ??? (in /usr/lib/libglib-2.0.so.0.5200.2)
==1191==    by 0x4AB0FD7: g_main_loop_run (in /usr/lib/libglib-2.0.so.0.5200.2)
==1191==    by 0x497389F: ??? (in /usr/lib/libgio-2.0.so.0.5200.2)
==1191==    by 0x4AD9B3B: ??? (in /usr/lib/libglib-2.0.so.0.5200.2)
==1191==  Address 0x86ac014 is 20 bytes inside a block of size 24 free'd
==1191==    at 0x4846EC8: free (vg_replace_malloc.c:530)
==1191==    by 0x113FFD: __netconfig_wifi_bssid_create_interface (wifi-bssid-scan.c:454)
==1191==    by 0x113FFD: __netconfig_wifi_bssid_scan (wifi-bssid-scan.c:486)
==1191==    by 0x113FFD: handle_request_bssid_scan (wifi-bssid-scan.c:529)
==1191==    by 0x4E45AF7: ffi_call_SYSV (in /usr/lib/libffi.so.6.0.2)
==1191==  Block was alloc'd at
==1191==    at 0x48458A4: malloc (vg_replace_malloc.c:299)
==1191==    by 0x4AB61B3: g_malloc (in /usr/lib/libglib-2.0.so.0.5200.2)
==1191==    by 0x4ACF4A3: g_slice_alloc (in /usr/lib/libglib-2.0.so.0.5200.2)
==1191==    by 0x4AF01EF: ??? (in /usr/lib/libglib-2.0.so.0.5200.2)
==1191==    by 0x4AEC8E7: g_variant_builder_end (in /usr/lib/libglib-2.0.so.0.5200.2)
==1191==    by 0x4AEE6C7: ??? (in /usr/lib/libglib-2.0.so.0.5200.2)
==1191==    by 0x4AEE9FF: g_variant_new_va (in /usr/lib/libglib-2.0.so.0.5200.2)
==1191==    by 0x4AEEAC3: g_variant_new (in /usr/lib/libglib-2.0.so.0.5200.2)
==1191==    by 0x113FB7: __netconfig_wifi_bssid_create_interface (wifi-bssid-scan.c:438)
==1191==    by 0x113FB7: __netconfig_wifi_bssid_scan (wifi-bssid-scan.c:486)
==1191==    by 0x113FB7: handle_request_bssid_scan (wifi-bssid-scan.c:529)
==1191==    by 0x4E45AF7: ffi_call_SYSV (in /usr/lib/libffi.so.6.0.2)

Change-Id: If9fa9f2a0e6e2b6f201a486d333ed153c0581b98
Signed-off-by: Niraj Kumar Goit <niraj.g@samsung.com>