Merge branch 'stable-4.11' into stable-5.0

Merge branch 'stable-4.11' into stable-5.0

* stable-4.11:
  Prepare 4.11.5-SNAPSHOT builds
  JGit v4.11.4.201810060650-r
  Fix configuration of maven-javadoc-plugin
  Prepare 4.9.7-SNAPSHOT builds
  JGit v4.9.6.201810051924-r
  Prepare 4.7.6-SNAPSHOT builds
  JGit v4.7.5.201810051826-r
  BaseReceivePack: Validate incoming .gitmodules files
  ObjectChecker: Report .gitmodules files found in the pack
  SubmoduleAddCommand: Reject submodule URIs that look like cli options

* Fix configuration of maven-javadoc-plugin for site generation

Change-Id: Ic6ff8d324867ee41f15a5b890c7eee5092e8453e
Signed-off-by: Jonathan Nieder <jrn@google.com>
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>