Readd object-storage-manual for Grizzly

Change I698fd3481915017dc3f862253757716c5105128b removed the
object storage manual since the guide has been obsoleted. But we
still need to build it for Grizzly, so readd for Grizzly only.

Change-Id: I3fa703bf94f5dc7ba377d0b91fd9138c83e4981f
Move stevedore to stackforge

Change-Id: I39592564213edfe1ce0241ea7215e650ee47fd16
Merge "Move stevedore to stackforge"
Merge "Readd object-storage-manual for Grizzly"