Update stevedore

Stevedore 0.12 comes with a new shiny map_method function that
Ceilometer would like to use.

Change-Id: If4eda8ed2e251df67ccfe9f8093d28d2ecbd740e
Add taskflow (used by cinder + others) to requirements

Taskflow (a stackforge based library) targeted at helping
openstack projects with state management and consistency
is now offically a library and to remove the cinder local
copy we need to add it as a requirement.

Change-Id: Ic112d707b3d914481da41adbb6aa9d8b890742df
Merge "Add taskflow (used by cinder + others) to requirements"
Released 0.1.1 for taskflow (bug fixes)

Bump the version of taskflow since we just pushed out a
minor bug fix release to address some issues that we
discovered after the 0.1 release (minor bugs), so mirroring
that version bump in requirements repo.

Change-Id: Id84eb4c7592c02f90090b557fe0faefcb6bdc3db
Merge "Update stevedore"