Add more error checking for ndc

In NativeDaemonConnector.doCommand() calls, there was inconsistent error
checking. This change adds error checking for every call and makes it so
that any call to .doCommand() that gets an error code won't cause the
code to hang forever.

Change-Id: I4584953a759a48ad16adfe8ee9e564b5f5796680
3 files changed