Use JGit 4.5.4
Use JGit 4.5.4

See https://projects.eclipse.org/projects/technology.jgit/releases/4.5.4
for details.

Fix some cases of incorrect handling of NFS file locking.

MarkEWaite/git-client-plugin,MarkEWaite/git-client-plugin,MarkEWaite/git-client-plugin