obslog: make content and description patches available to templater The code was repeatedly calling fm.write() with the same field ("patch" and "descdiff"). I think that led to the value constantly getting replaced, so when it was used in a template (as {patch} or {descdiff}), it would only get the last value, which was always an empty string. This patch fixes it by writing the full patch to a temporary buffer and then assigning the whole patch to the formatter field.

#require test-repo pyflakes

Copied from Mercurial core (60ee2593a270)

  $ cd "`dirname "$TESTDIR"`"

run pyflakes on all tracked files ending in .py or without a file ending
(skipping binary file random-seed)

  $ hg locate -I 'set:(**.py or grep("^#!.*python")) - removed()' 2>/dev/null \
  > | xargs pyflakes 2>/dev/null