Wrap python2.7 error message

[PrajwalM2212]

Wraps python2.7 error message with user-friendly error message

Resolves #362

Signed-off-by: Prajwal M [email protected]

[PrajwalM2212]

@nishakm @rnjudge Can you review this ?

[PrajwalM2212]

In #362

The error is being hit in tern/classes/docker_image.py. Might consider using the traceback library: https://docs.python.org/3/library/traceback.html

Another option would be for Tern to check for dependencies somehow before running.

@rnjudge I chose to check for dependencies before running. If I wrap the error in docker_image.py, it may turn up in some other class, so I thought that it would good to check for dependencies before running.

[nishakm]

@PrajwalM2212 this is a reasonable fix. I will merge this.