minor, actually barf if file passed to tzmap check command cannot be checked

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
minor, run fetched or distributed tzmaps through tzmap check
fix, PEBKAC, reset line checker check_line() after EOF of file

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
Merge branch 'feat/tzmap-check'

* feat/tzmap-check:
  fix, PEBKAC, reset line checker check_line() after EOF of file
  minor, run fetched or distributed tzmaps through tzmap check
  minor, actually barf if file passed to tzmap check command cannot be checked