fatal function may impede the downstream APIs functionality

[Raviteja-Ainampudi]

credstash/credstash.py

Line 165 in df24f91

sys.exit(1)

I suggest removing the os.exit(1) because, it might hinder the functionality of any downstream API.
I'm not sure, if that line of code will actually help the functionality of Credstash.

My experience:
I was trying to use Credstash in AWS lambda, and need to extract passwords for a list of keys. But, this sys.exit(1) causes the whole lambda to exit. Ofcourse, I can change the source code. But I want to suggest this such that the scope of Credstash can be improved among the developer community. If anybody is having Credstash among their Upstream APIs.