Remove old jgit jar from build repo

jgit should be provided by the eclipse repo so we use the same version
of jgit as the base eclipse version we support. This should fix the
windows test failure when there is a space in the workspace path. See
https://github.com/bndtools/bndtools/pull/891 for some discussion.

Signed-off-by: BJ Hargrave <bj@bjhargrave.com>