dl_bikedata london dates not parsed correctly

[mpadge]

> dl_bikedata(city = "lo", dates = 201101)
Downloading 11a-Journey-Data-Extract-18Oct15-31Oct15.csv
Downloading 11b-Journey-Data-Extract-01Nov15-14Nov15.csv
Downloading 11JourneyDataExtract22Jun2016-28Jun2016.csv
Downloading 26JourneyDataExtract05Oct2016-11Oct2016.csv
Downloading 40JourneyDataExtract11Jan2017-17Jan2017.csv
Downloading 52JourneyDataExtract05Apr2017-11Apr2017.csv
Downloading 65JourneyDataExtract05Jul2017-11Jul2017.csv
Downloading 79JourneyDataExtract11Oct2017-17Oct2017.csv
Downloading 7a.JourneyDataExtract28Jun15-11Jul15.csv