Merge branch '6.4' into 7.4

* 6.4:
  [Console] Keep messages containing malformed UTF-8 when wrapping
  [Finder] Only treat a leading hash as a gitignore comment and strip trailing spaces only
  [FrameworkBundle] Fix the fatal when a cache pool cannot be cleared
  [Mailer] Reconnect when the server closed the transmission channel
  [Finder] Fix building the gitignore regex for files with many patterns
  [Finder] Fix ignoreVCSIgnored() when the search directory is reached through a symlink

# Conflicts:
#	src/Symfony/Bundle/FrameworkBundle/Tests/Command/CachePoolClearCommandTest.php