Add private_key_passwd field

[GoogleCodeExporter]

What steps will reproduce the problem?
1. Configure profile for TLS which requires the use of private key.
2. Enter private-key path (e.g. /sdcard/user.pfx).
3. No field to enter private-key password.

What is the expected output? What do you see instead?
When the profile is saved, a field private_key_passwd must also be populated 
with the user supplied private-key password.

What version of the product are you using? On what operating system?
Android 2.3

Please provide any additional information below.

Original issue reported on code.google.com by [email protected] on 5 Apr 2012 at 1:36