r21896: - Enable creating default NetContext when no explicit credentials are

r21896: - Enable creating default NetContext when no explicit credentials are
  passed. In such case use what's been provided on swat session logon.
- Create a proper NetContext object only once and add it to the resources
  for later use.

rafal
(This used to be commit 106779fcf3bf96eaa82adfa020a31a4634afda43)