Merge branch 'stable-5.5' into stable-5.6

Merge branch 'stable-5.5' into stable-5.6

* stable-5.5:
  Fix API problem filters
  Fix unclosed resource warning in SmartOutputStream
  JschConfigSessionFactory: fix boxing warning
  SshSupport#runSshCommand: don't throw exception in finally block
  Don't override already managed maven-compiler-plugin version
  Remove unused import from CreateFileSnapshotBenchmark
  Remove duplicate ignore_optional_problems entry in .classpath
  Update maven-site-plugin used by benchmark module to 3.8.2
  Add dependency to enable site generation for benchmark module
  Ignore warnings for generated source code in
org.eclipse.jgit.benchmark
  Fix MBean registration
  Enhance WindowCache statistics

Change-Id: I11f9a387ac3dc7d22a4f2e70bb8d89169b4e9afe
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>