Fix Edit Wiki Page without previous revision ID
Fix Edit Wiki Page without previous revision ID

nyanpasudo/RedditSharp,SirCmpwn/RedditSharp,pimanac/RedditSharp,angelotodaro/RedditSharp,CrustyJew/RedditSharp,tomnolan95/RedditSharp,Jinivus/RedditSharp,chuggafan/RedditSharp-1,justcool393/RedditSharp-1,RobThree/RedditSharp