Slightly refactor  misc::statistics::limn::mobile_data_sync

This will allow for multliple teams to more easily run generate.py
and sync data over to stat1001 using different limn dataset sources.

TODO: put generate.py into a generic limn generator repository,
rather than requiring that limn-mobile-data repo is cloned
for all limn::data::generate jobs.

Change-Id: Iec0f862ca3e4ee63570f1c495260807071b1e2a4