Fix ps() by fixing FastAsyncTask tag creation.
Fix ps() by fixing FastAsyncTask tag creation.

	* src/kernel/userver.cc: Create the tag in initialize,
	not the ctor where Tag::proto does not yet exists.

urbiforge/urbi,aldebaran/urbi,urbiforge/urbi,aldebaran/urbi,aldebaran/urbi,urbiforge/urbi,urbiforge/urbi,urbiforge/urbi,urbiforge/urbi,aldebaran/urbi,aldebaran/urbi,urbiforge/urbi,aldebaran/urbi,urbiforge/urbi,aldebaran/urbi,urbiforge/urbi,aldebaran/urbi