#1570 cbplugin: better validation check in ConsoleInfo

[Sergey Katunin]

cbplugin: better validation check in ConsoleInfo

There is case on slow PCs, that console pid is ready, but ttyPath is not yet.
This is happening if debugger launch terminal with some wrapper like 'xdg-terminal' that launches 'xterm' (for example).

So now check has been strengthened in ConsoleInfo:
ConsoleInfo is invalid not only when 'ttyPath' is empty, but when it is not ready yet ('/dev/?') too.

Tested on Linux