Revert "Ensure gif avatar urls end in `.gif`"
Revert "Ensure gif avatar urls end in `.gif`"

This reverts commit 456390f417e63126b08ac52fa8ee49ca68cefed8.

This commit isn't needed anymore - the image proxy now properly
handles gifs that do not end in .gif

khazhyk/discord.py,imayhaveborkedit/discord.py,rapptz/discord.py,Harmon758/discord.py,Rapptz/discord.py,Harmon758/discord.py