[PATCH, take 2] libertas: reduce command retry time

In the normal case, an unsuccessful command would be retried for 10*5 seconds,
or 10*10 seconds in the worst case. This patch reduces this to 3*3 seconds,
or 3*10 seconds in the worst case.

I also reduced the time it takes to start a new command downloaded.
Signed-off-by: Holger Schurig <hs4233@mail.mn-solutions.de>
Acked-by: Dan Williams <dcbw@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>