Change to cron job to adapt to stat1

  * cron-script.sh now copies csv to /a/wikistats_git/dumps/csv/csv_sp/
  * added safety check for invalid time (did actually found a line with
                                         invalid time in 2013-03-02 line 4371072)

Change-Id: I35cd8e66fb1f2f6010013b1a9eeccba7ee1f6716