Update diskspace()

Add hdd icon.

bumblebee/modules/disk.py

@@ -1,7 +1,7 @@
 # pylint: disable=C0111,R0903
 
 """Shows free diskspace, total diskspace and the percentage of free disk space.
--
+
 Parameters:
     * disk.warning: Warning threshold in % of disk space (defaults to 80%)
     * disk.critical: Critical threshold in % of disk space (defaults ot 90%)
@@ -28,7 +28,7 @@ class Module(bumblebee.engine.Module):
             cmd="nautilus {}".format(self._path))
 
     def diskspace(self, widget):
-        return "{} {}/{} ({:05.02f}%)".format(self._path,
+        return "\uf0a0 {} {}/{} ({:05.02f}%)".format(self._path,
             bumblebee.util.bytefmt(self._used),
             bumblebee.util.bytefmt(self._size), self._perc
         )