Raise a different exception if ffmpeg is not found in PATH.
Raise a different exception if ffmpeg is not found in PATH.

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