c/file: improve upload error handling
c/file: improve upload error handling

Signed-off-by: Florian Pritz <753f544d2d01592750fb4bd29251b78abcfc8ecd@xinu.at>

jreinert/filebin,jreinert/filebin,jreinert/filebin,Bluewind/filebin,Bluewind/filebin,jreinert/filebin,Bluewind/filebin,Bluewind/filebin,jreinert/filebin,jreinert/filebin,Bluewind/filebin