Gracefully handle missing private key (SCRD-7489)
Gracefully handle missing private key (SCRD-7489)

When load the private key, gracefully handle the situation where the
file is missing.

Change-Id: I6d621cf8c2aa7cf05145befa18342a3f4b1bb192

ArdanaCLM/ardana-service,ArdanaCLM/ardana-service