Transaction to create objects (or not) is currently tied to the
repository, but in the future a repository can have multiple object
sources, which may have different transaction mechanisms. Make the
odb transaction API per object source.
* jt/odb-transaction-per-source:
odb: transparently handle common transaction behavior
odb: prepare `struct odb_transaction` to become generic
object-file: rename transaction functions
odb: store ODB source in `struct odb_transaction`
projects / thirdparty / git.git / commit
