Resolve Bug:623 : Generate private key using bouncycastle.

Add dependency on bouncycastle and use it to generate private key in PEM
format when key file is not present on the filesystem.

Change-Id: I07290e0f361151743a50559c26255eab23cababb
Signed-off-by: Tomas Olvecky <tolvecky@cisco.com>
Merge "Resolve Bug:623 : Generate private key using bouncycastle."