bluez-tools FTBFS on wily-proposed due to AM_LDFLAGS misuse

bluez-tools FTBFS in wily-proposed with the following error:

gcc -g -O2 -fstack-protector-strong -Wformat -Werror=format-security -lglib-2.0 -lgio-2.0 -lgobject-2.0 -lglib-2.0 -Wl,-Bsymbolic-functions -Wl,-z,relro -o bt-adapter lib/agent-helper.o lib/dbus-common.o lib/helpers.o lib/manager.o lib/obex_agent.o lib/properties.o lib/sdp.o lib/bluez/adapter.o lib/bluez/agent_manager.o lib/bluez/alert_agent.o lib/bluez/alert.o lib/bluez/cycling_speed.o lib/bluez/cycling_speed_manager.o lib/bluez/device.o lib/bluez/health_channel.o lib/bluez/health_device.o lib/bluez/health_manager.o lib/bluez/heart_rate.o lib/bluez/heart_rate_manager.o lib/bluez/media.o lib/bluez/media_control.o lib/bluez/media_player.o lib/bluez/network.o lib/bluez/network_server.o lib/bluez/obex/obex_agent_manager.o lib/bluez/obex/obex_client.o lib/bluez/obex/obex_file_transfer.o lib/bluez/obex/obex_message_access.o lib/bluez/obex/obex_message.o lib/bluez/obex/obex_object_push.o lib/bluez/obex/obex_phonebook_access.o lib/bluez/obex/obex_session.o lib/bluez/obex/obex_synchronization.o lib/bluez/obex/obex_transfer.o lib/bluez/profile_manager.o lib/bluez/proximity_monitor.o lib/bluez/proximity_reporter.o lib/bluez/sim_access.o lib/bluez/thermometer.o lib/bluez/thermometer_manager.o bt-adapter.o
lib/agent-helper.o: In function `_find_device_pin':
/«PKGBUILDDIR»/src/lib/agent-helper.c:329: undefined reference to `g_hash_table_lookup'
/«PKGBUILDDIR»/src/lib/agent-helper.c:330: undefined reference to `g_hash_table_lookup'
<snip>
/«PKGBUILDDIR»/src/bt-adapter.c:301: undefined reference to `g_variant_get_uint32'
/«PKGBUILDDIR»/src/bt-adapter.c:302: undefined reference to `g_ascii_strcasecmp'
/«PKGBUILDDIR»/src/bt-adapter.c:303: undefined reference to `g_variant_get_boolean'
collect2: error: ld returned 1 exit status
make[3]: *** [bt-adapter] Error 1
Makefile:574: recipe for target 'bt-adapter' failed
make[3]: Leaving directory '/«PKGBUILDDIR»/src'
make[2]: *** [all-recursive] Error 1
Makefile:362: recipe for target 'all-recursive' failed
make[2]: Leaving directory '/«PKGBUILDDIR»'
make[1]: *** [all] Error 2
Makefile:303: recipe for target 'all' failed
make[1]: Leaving directory '/«PKGBUILDDIR»'
dh_auto_build: make -j1 returned exit code 2
make: *** [build] Error 2
debian/rules:8: recipe for target 'build' failed
dpkg-buildpackage: error: debian/rules build gave error exit status 2

See https://launchpadlibrarian.net/214393772/buildlog_ubuntu-wily-amd64.bluez-tools_0.2.0~20140808-3_BUILDING.txt.gz

This is due to the libraries being set in LDFLAGS while they should actually be set on LIBS or LDADD [1,2].

[1] http://www.gnu.org/savannah-checkouts/gnu/autoconf/manual/autoconf-2.69/html_node/Preset-Output-Variables.html#index-LDFLAGS-112
[2] http://www.gnu.org/software/automake/manual/html_node/Linking.html