Fixes SR setting SeedIdleLimit no matter what

Any setting will set a SeedIdleLimit in Transmission even if your client default is to not have SeedIdleLimit enabled. This allows a setting of '-1' to bypass setting the SeedIdleLimit thereby not stopping torrent seeding based on this limit.
I went on the assumption that 0 was a default for a reason, that it didn't set an idle time for other clients which is why i added -1 as 0 still sets the idle time for Transmission. If this isn't the case i can adjust it.