Introduce context parameter for ExpandPromise

This allows to evaluate subordinate promises, which need information to be
passed from the parent one (such as ones in files_edit bundles).
De-duplicate exit paths in ScheduleEditOperation
Move edcontext out of Promise struct
Fix traversal of 'abstract' directories
Revert "Use AgentConnection *, not FileCopy.servers to check whether the network access is required"

This reverts commit eefc77537bb757a25d0823c53f533f8a7b22f5e3.