am f50c7fb0: Merge change 2252 into donut

Merge commit 'f50c7fb0842c403edc47ea7258af06e7fd1f262c'

* commit 'f50c7fb0842c403edc47ea7258af06e7fd1f262c':
  Fix the java.lang.StringIndexOutOfBoundsException that occurs when an SMTP server closes the connection early or returns an empty line.