PrivateKeyFile constructor requires write access to private key file

[GoogleCodeExporter]

What steps will reproduce the problem?
1. grant your app user read only permissions to the private key file
2. try to construct a PrivateKeyFile object on that file.
3. Watch it puke.

What is the expected output? What do you see instead?
The app should NOT require write/modify/full control access to the private key 
file.  The code should be changed to open the file in read only mode.

What version of the product are you using?  dll says version: 2013.4.7.0

Server OS: Windows (any version).  I'm using windows 8.
Ssh server: any





Please provide any additional information below.

Original issue reported on code.google.com by tonyschw...@gmail.com on 17 Mar 2015 at 12:52