record: use absolute path instead of os.chdir...
record: use absolute path instead of os.chdir
Record was changing the current directory to `repo.root` in order to be able to
feed `command.commit` file name relative to this `repo.root`. This is a bit
overkill and prevent an incoming fix to rebase. This would also break
multi-threaded usage.
Instead we just feed `command.commit` with absolute path name. works as well as
before but without chdir.
