tests/test-gendoc-de.t

sparse: clean up config signature code

Before, 0 was being used as the default signature value and we cast
the int to a string. We also handled I/O exceptions manually.

The new code uses cfs.tryread() so we always feed data into the
hasher. The empty string does hash and and should be suitable
for input into a cache key.

The changes made the code simple enough that the separate checksum
function could be inlined.

#require docutils gettext

  $ $TESTDIR/check-gendoc de
  checking for parse errors
  Die Dateien werden dem Projektarchiv beim n\xc3\xa4chsten \xc3\x9cbernehmen (commit) hinzugef\xc3\xbcgt. Um dies vorher r\xc3\xbcckg\xc3\xa4ngig zu machen, siehe:hg:`forget`. (esc)
  warning: please have a space before :hg: