Move widget configurations to _configure

The `Mpd2` and `PulseVolume` widgets have code in their `__init__`
methods that is better suited to the `_configure` method.

libqtile/widget/mpd2widget.py

@@ -177,11 +177,14 @@ def __init__(self, **config):
         super().__init__("", **config)
 
         self.add_defaults(Mpd2.defaults)
+        if self.color_progress:
+            self.color_progress = utils.hex(self.color_progress)
+
+    def _configure(self, qtile, bar):
+        super()._configure(qtile, bar)
         self.client = MPDClient()
         self.client.timeout = self.timeout
         self.client.idletimeout = self.idletimeout
-        if self.color_progress:
-            self.color_progress = utils.hex(self.color_progress)
 
     @property
     def connected(self):

libqtile/widget/pulse_volume.py

@@ -51,6 +51,8 @@ def __init__(self, **config):
         self.handle = ffi.new_handle(self)
         self.client_name = ffi.new("char[]", b"Qtile-pulse")
 
+    def _configure(self, qtile, bar):
+        Volume._configure(self, qtile, bar)
         self.connect()
 
     def finalize(self):