Reduce the dependency on the ClientSession in preparation to
remove it altogether. Remove the internal helper, re-implement
the needed bits. We have not implemented any configuration
possibility in JGit for creating hashed host names in known hosts
files, so we don't need the sshd code that theoretically would
enable this.
Change-Id: I295f5106b60e1cc3a9d085b0cb7ff747daae88be Signed-off-by: Thomas Wolf <thomas.wolf@paranor.ch>