wrap wget in hide_output so that wget errors are shown

Our wget_verify function uses wget to download a file and then check
the file's hash. If wget fails, i.e. because of a 404 or other HTTP
or network error, we exited setup without displaying any output because
normally there are no errors and -q keeps the setup output clean.

Wrapping wget with our hide_output function, and dropping -q, captures
wget's output and shows it and exits setup just if wget fails.

see #1297

setup/functions.sh

@@ -179,7 +179,7 @@ function wget_verify {
 	DEST=$3
 	CHECKSUM="$HASH  $DEST"
 	rm -f $DEST
-	wget -q -O $DEST $URL || exit 1
+	hide_output wget -O $DEST $URL
 	if ! echo "$CHECKSUM" | sha1sum --check --strict > /dev/null; then
 		echo "------------------------------------------------------------"
 		echo "Download of $URL did not match expected checksum."