Makefile.am: fix whitespace
build-sys: fix linking order

./.libs/libsystemd-network.a(libsystemd_network_la-network-internal.o):
  network-internal.c:function net_get_unique_predictable_data:
  error: undefined reference to 'udev_device_get_property_value'
collect2: error: ld returned 1 exit status
build-sys: do not run symbol list export test for compat-only libs

The verbose link-time deprecation warnings are annoying. These libs
will never change or be extended; there is no need to test the list
of exported symbols.