Updated incremental loading sample script

For #774
Remove bogus comment from archive.xml descriptor

This comment came with a copy-paste-edit but was never deleted/updated
to reflect the local edits
Merge branch 'titan05' of github.com:thinkaurelius/titan into titan05
Fix getOrCreateVertexProperty param name

This name change is cosmetic and does not affect the signature of the
getOrCreateVertexProperty incremental loading method.  Intent of this
commit is just to make the code less confusing.