Not returning Error Code when exiting due to unsynced node on Windows

[mwferris]

When the node becomes unsynchronized after the miner has started, the miner prints the error -4077: might be that the full node is not synced, ... to output but if you try and get the error code for the process there is none.

get-process gpu-miner | select HasExited, ExitCode

shows that the process has not exited and not returned any exit code, but it is no longer mining.