Handle no new data more elegantly

[joeHickson]

If there's no new data to process the summary data errors

2021-01-31 21:01:47 INFO Data has not been updated since last run. If wanting to run again then remove /home/rstudio/covid-rt-estimates/last-update/colombia.rds
2021-01-31 21:01:47 DEBUG Max date in data - 2021-01-30, last run date from file - 2021-01-30
2021-01-31 21:01:47 DEBUG add stats to output
2021-01-31 21:01:47 WARN simpleWarning in system(paste0("for f in ", location$target_folder, "/*/latest/summary.rds; do git log -n 1 --pretty=format:\"%ad\" --date=iso -- \"$f\" 2>/dev/null; done"), : running command 'for f in subnational/colombia/cases/national/*/latest/summary.rds; do git log -n 1 --pretty=format:"%ad" --date=iso -- "$f" 2>/dev/null; done' had status 128
2021-01-31 21:01:47 WARN simpleWarning in gsub("~m", msg, message, fixed = TRUE): argument 'replacement' has length > 1 and only the first element will be used
2021-01-31 21:01:47 WARN simpleWarning in gsub("~m", msg, message, fixed = TRUE): argument 'replacement' has length > 1 and only the first element will be used
2021-01-31 21:01:47 WARN colombia: simpleWarning in system(paste0("for f in ", location$target_folder, "/*/latest/summary.rds; do git log -n 1 --pretty=format:\"%ad\" --date=iso -- \"$f\" 2>/dev/null; done"), : running command 'for f in subnational/colombia/cases/national/*/latest/summary.rds; do git log -n 1 --pretty=format:"%ad" --date=iso -- "$f" 2>/dev/null; done' had status 128
2021-01-31 21:01:47 DEBUG git not working - try stat
stat: cannot stat 'subnational/colombia/cases/national/*/latest/summary.rds': No such file or directory
2021-01-31 21:01:47 WARN simpleWarning in system(paste0("for f in ", location$target_folder, "/*/latest/summary.rds; do stat -c %y $f; done"), : running command 'for f in subnational/colombia/cases/national/*/latest/summary.rds; do stat -c %y $f; done' had status 1
2021-01-31 21:01:47 WARN simpleWarning in gsub("~m", msg, message, fixed = TRUE): argument 'replacement' has length > 1 and only the first element will be used
2021-01-31 21:01:47 WARN simpleWarning in gsub("~m", msg, message, fixed = TRUE): argument 'replacement' has length > 1 and only the first element will be used
2021-01-31 21:01:48 WARN colombia: simpleWarning in system(paste0("for f in ", location$target_folder, "/*/latest/summary.rds; do stat -c %y $f; done"), : running command 'for f in subnational/colombia/cases/national/*/latest/summary.rds; do stat -c %y $f; done' had status 1

If there's no change there'll be no timing data. Also don't publish.