* Fix modified files list in webhooks when there is a space
There is an unfortunate bug with GetCommitFileStatus where files with
spaces are misparsed and split at the space.
There is a second bug because modern gits detect renames meaning that
this function no longer works correctly.
There is a third bug in that merge commits don't have their modified
files detected correctly.
Fix#15865
This PR improves HasPreviousCommit to prevent the automatic and recursive loading
of previous commits using git merge-base --is-ancestor and git rev-list
Fix#13684
zeripath
6543
Lunny Xiao