Singularity 2.4.2 Release

Hello Singularity world!

This is a minor bug fix release which includes the following changes:

• This fixed an issue for support of older distributions and kernels with regards to setns()
  functionality.
• Fixed autofs bug path (lost during merge)

As usual, please report any additional bugs to:
https://github.com/singularityware/singularity/issues/new