Upgrade JGit to 4.7.6.201810191618-r
Upgrade JGit to 4.7.6.201810191618-r

It contains fix for 'LFS: file handle leak in ObjectDownloadListener'
issue ([1])

[1] https://bugs.eclipse.org/bugs/show_bug.cgi?id=540049

Change-Id: I10d138cdb6bbb33a3511156f6abc238c9285a007
Signed-off-by: Jacek Centkowski <ce4a73803a80af51ece4477dad59cc7b1801c73e@collab.net>

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