[commit/obvious] Fix PR 21352: Command tsave does not support -r argument

[Pedro Alves]

On 04/05/2017 05:31 PM, Sergio Durigan Junior wrote:
> This is an obvious fix for PR 21352.  The problem is that the argument
> parsing loop is not using an "else if" where it should, and therefore
> the '-r' option ends up unrecognized by GDB.

We have a few tests under gdb.trace/ that exercise "tsave".  Would it
be easy to augment some to exercise this?

Thanks,
Pedro Alves