log: include unmodified-in-merge files in log diff/stat (issue2383) f786fc4b8764 assumed that walkchangerevs called prep with all relevant matched filenames, but actually it only contains the names of files changed in the relevant changeset. That meant that log diff/stat of merges missed the diff for files only changed in the other branch. This is a minimal fix for making sure we only use fns when we are following and thus will have problems with merges anyway ...

tests: fix unzip -l variability fix 01-01-1980 slipped through the grep.

merge with stable

tests: fix unzip -l variability

mq: always require --force when pushing patches (issue2363) --force was not necessary when passing --rev since 55578a8d7e84, but this behaviour is usually harmful when branch names are passed instead of explicit revisions.

tests: various fixes for new unified test pattern format