Fix IndexError in Client.move_member.
Fix IndexError in Client.move_member.

jhgg/discord.py,Theoretical/UselessBot,imayhaveborkedit/discord.py,lgkern/PriestPy,rapptz/discord.py,mgardne8/discord.py,khazhyk/discord.py,Rapptz/discord.py,Harmon758/discord.py,variablehair/Eggplantato,Harmon758/discord.py