Make fdbcli gracefully handle malformed and partial command errors.

Previously, running a command like `set \xffx\02abcded/` would cause a crash.
The `x\02` is a malformed typo of `\x02`, and the previously existing code to
handle this case looks like

    loop {
      err = parse_command
      if (err)  continue;
      // do things
    }

Thus, if we hit an error, we'd go back to the top of the loop, and try again.
This should be an infinite loop.  However, the actor compiler implementation of
loops involves function calls, so this actually turns into a series of the loop
head calling the loop body calling the loop head calling ... and we eventually
crash due to running out of stack.

This is now fixed by simply letting the code continue on to the check later
that does

    if (there was an error) {
      print nasty message
      return error
    }

With output that looks like

    ERROR: malformed escape sequence
    WARNING: the previous command failed, the remaining commands will not be executed.

And therefore the world becomes a happy place.

fdbcli/fdbcli.actor.cpp

@@ -2222,12 +2222,10 @@ ACTOR Future<int> cli(CLIOptions opt, LineNoise* plinenoise) {
 			if (err) {
 				LogCommand(line, randomID, "ERROR: malformed escape sequence");
 				is_error = true;
-				continue;
 			}
 			if (partial) {
 				LogCommand(line, randomID, "ERROR: unterminated quote");
 				is_error = true;
-				continue;
 			}
 
 			state bool multi = parsed.size() > 1;