libnm: make the the use of GInitable mandatory

Remove _nm_object_ensure_inited(), etc; objects that implement
GInitable are now mandatory-to-init().

Remove constructor() implementations that sometimes return NULL; do
all the relevant checking in init() instead.

Make nm_client_new() and nm_remote_settings_new() take a GCancellable
and a GError**.

examples/python/gi/device-state-ip4config.py

@@ -51,7 +51,7 @@ if __name__ == "__main__":
         sys.exit('Usage: %s <interface>' % sys.argv[0])
     dev_iface = sys.argv[1]
 
-    c = NM.Client.new()
+    c = NM.Client.new(None)
     dev = c.get_device_by_iface(dev_iface)
     if dev is None:
         sys.exit('Device \'%s\' not found' % dev_iface)

examples/python/gi/get-active-connections.py

@@ -24,7 +24,7 @@
 from gi.repository import GLib, NM
 
 if __name__ == "__main__":
-    client = NM.Client.new()
+    client = NM.Client.new(None)
     acons = client.get_active_connections()
     for ac in acons:
         print "%s (%s) - %s" % (ac.get_id(), ac.get_uuid(), ac.get_connection_type())

examples/python/gi/get_ips.py

@@ -124,7 +124,7 @@ if __name__ == "__main__":
         sys.exit('Usage: %s <interface>' % sys.argv[0])
     dev_iface = sys.argv[1]
 
-    c = NM.Client.new()
+    c = NM.Client.new(None)
     dev = c.get_device_by_iface(dev_iface)
     if dev is None:
         sys.exit('Device \'%s\' not found' % dev_iface)

examples/python/gi/show-wifi-networks.py

@@ -62,7 +62,7 @@ def print_ap_info(ap):
     print
 
 if __name__ == "__main__":
-    nmc = NM.Client.new()
+    nmc = NM.Client.new(None)
     devs = nmc.get_devices()
 
     for dev in devs: