Fix the Internal Field Seperator when using ethtool

ethtool.sh didn't reset the Internal Field Seperator (IFS) properly.
It now does, by storing the old IFS to OIFS, which will be used later
in the for loop.

It also fixes the "ethtool_ring_<if>" option.

Reported-by: Alois Schmid <alois.schmid@gmx.de>
X-Gentoo-Bug: 368525
X-Gentoo-Bug-URL: https://bugs.gentoo.org/368525

net/ethtool.sh

@@ -31,6 +31,7 @@ ethtool_pre_start() {
 		[ -z "${args}" ] && continue
 
 		# Split on \n
+		OIFS="${IFS}"
 		local IFS="$__IFS"
 
 		for p in ${args} ; do
@@ -38,6 +39,7 @@ ethtool_pre_start() {
 			local args_pretty="$(_trim "${p}")"
 			# Do nothing if empty
 			[ -z "${args_pretty}" ] && continue
+			[ "${opt}" = "ring" ] && opt="set-ring"
 			args_pretty="--${opt} $IFACE ${args_pretty}"
 			args="--${opt} $IFACE ${args}"
 			ebegin "ethtool ${args_pretty}"