Fix reset relatedEps before renaming

http://www.sickbeard.com/forums/viewtopic.php?f=4&t=7571

Reproduced it like this:

Rename in Sickbeard using "wrong" naming scheme: %Sx%0E-%EN
Episode name starts with number.
Now you have multi-episode in database.

Change naming scheme to correct one.

Rename on harddisk to: %Sx%0E
In SickBeard: Show -> Re-scan files
Looks correct in database
Hit Preview Rename again, treats episode still as multi-episode

(But guess it could also happen when you start with a S01E01-02 do a rename, but find out it's only S01E01 and follow same steps)

If you restart SickBeard after Re-scan files it renames correctly second time.