In preparation for porting to GDBus, make nm_connection_to_dbus(),
etc, represent connections as GVariants of type 'a{sa{sv}}' rather
than as GHashTables-of-GHashTables-of-GValues.
This means we're constantly converting back and forth internally, but
this is just a stepping stone on the way to the full GDBus port, and
all of that code will go away again later.
NMParamSpecSpecialized existed basically to provide a version of
GParamSpecBoxed that could compare dbus-glib-valued properties
correctly.
However, g_param_values_cmp() was only used by NM directly in one
place (NMSetting's compare_property()), and we don't actually need to
indirect through GParamSpec there; we could just call
NMParamSpecSpecialized's value-comparison function directly.
So, change all NMParamSpecSpecialized properties to GParamSpecBoxed,
rename the _gvalues_compare() function it used to
"nm_property_compare()", and use that from NMSetting.
(g_param_values_cmp() also gets used internally by
g_param_value_defaults(), but all NMParamSpecSpecialized properties
have a default value of NULL, so GParamSpecBoxed's pointer-equality
check will do the job just fine there.)
Make the formerly-nm-param-spec-specialized test compile (fix use of
inet_pton), and pass (include the mandatory "gateway" element in the
IPv6 addresses), make it use gtestutils and g_assert (so it actually
fails when it fails), and test a few more cases.
