Update swift element to install from source

The previous swift element only installed the swift package but didn't
setup anything beyond that.

This update results in 3 elements
swift         : common swift element
swift-proxy   : installs a swift proxy server
swift-storage : installs a swift storage server

Change-Id: I0b7eb4ce1d3d82fd4cf224f572f111d6801fac08
Use swift as a backend to glance

This commit will cause swift to be used as a backend to glance
if the heat metadata glance.backend = swift.

Change-Id: I4c4cc0c6763a91803ba51703a552a080d637abb0
Merge "Update swift element to install from source"
Merge "Use swift as a backend to glance"