bundle2: introduce a specific function for bundling debug message
The bundling process is very verbose, we would like to be able to hide such
output behind a configuration flag and have it more explicitly referencing
bundle2. The first step is to gather all these messages in a dedicated
function.
The same gathering will be later do for debug message issue by unbundling.
Test issue2761
$ hg init
$ touch to-be-deleted
$ hg add
adding to-be-deleted
$ hg ci -m first
$ echo a > to-be-deleted
$ hg ci -m second
$ rm to-be-deleted
$ hg diff -r 0
Same issue, different code path
$ hg up -C
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ touch does-not-exist-in-1
$ hg add
adding does-not-exist-in-1
$ hg ci -m third
$ rm does-not-exist-in-1
$ hg diff -r 1