Its a typo. Period.
I don't have a source, but I read some things that indicate that this is not a typo. So from now on the Sith are not from Korriban, they're from Morriband. It is a replacement that only illustrates a lack of creativity, seriously it's Korriban minus the "k" and plus an "m" and "d." Also, it just plain sounds worse. I'm convinced that this is just a retcon for the lols. Although, I wonder why they didn't pick a more creative name.