Merge branch 'master' into stable-5.9

Merge branch 'master' into stable-5.9

* master:
  SshdSession: close channel gracefully
  jgit: Add DfsBundleWriter
  Prepare 5.10.0-SNAPSHOT builds
  ResolveMerger: do not content-merge gitlinks on del/mod conflicts
  ResolveMerger: Adding test cases for GITLINK deletion
  ResolveMerger: choose OURS on gitlink when ignoreConflicts
  ResolveMerger: improving content merge readability
  ResolveMerger: extracting createGitLinksMergeResult method
  ResolveMerger: Adding test cases for GITLINK merge

Back out the version change to 5.10.0-SNAPSHOT which was done on master
already.

Change-Id: I1a6b1f0b8f5773be47823d74f593d13b16a601d5
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>