Return more error information for SslStream and NegotiateStream from *Pal.Unix.cs

[vijaykota]

Please see PR comment. We need to figure a way of passing the extended error information returned by the shim layer to the platform-agnostic code. Currently any exception is translated to SecurityStatusPal.InternalError

[shrutigarg]

This got fixed for sslstream in dotnet/corefx#6750 and the same has been done by @kapilash for negotiateStream changes in master.

[stephentoub]

and the same has been done by @kapilash for NegotiateStream changes in master

No. For example, this:
https://github.com/dotnet/corefx/blob/master/src/System.Net.Security/src/System/Net/NegotiateStreamPal.Unix.cs#L153
hasn't been updated.

[shrutigarg]

Will take a look. Thanks

[shrutigarg]

Updating this to
_return new Win32Exception(NTE_FAIL, statusCode.Exception.Message); _
will return this win32exception with an appropriate Error message.

[shrutigarg]

fix made in commit # 3 of dotnet/corefx#7647

[shrutigarg]

fixed an merged . closing