oeqa/runtime/ssh: check for all errors at the end

oeqa/runtime/ssh: check for all errors at the end

With the retry for the -SIGTERM, it is possible to still see that error
after the 5th attempt and mark the run a success.  Check for any
non-zero status in the final check and error out to close the gap.
While there, make the error print match the one above and be a little
more verbose.  Also, I'm seeing it take roughly 6 attempts on my local
(very slow) system to pass.  So, increasing the number of attempts to
10.

Signed-off-by: Jon Mason <jdmason@kudzu.us>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>