vcsim: Update Dockerfile

[embano1]

Description

The vcsim Dockerfile now uses ENTRYPOINT for the vcsim binary and
CMD for default listener address 0.0.0.0:8989. A user can now easily
overwrite the default behavior without having to specify /vcsim
explicitly since it is the defined ENTRYPOINT.

Signed-off-by: Michael Gasch mgasch@vmware.com

Closes: #2841

Type of change

Please mark options that are relevant:

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to
  not work as expected)
• This change requires a documentation update
• Build related change

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide
instructions so we can reproduce. If applicable, please also list any relevant
details for your test configuration.

• docker run vmware/vcsim (run with defaults)
• docker run vmware/vcsim -l :9090 (overwrite bind address

Checklist:

• My code follows the CONTRIBUTION guidelines of
  this project
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation (Docker Hub)
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged