net.lo: fix typo in previous math commit

x-Gentoo-Bug: 391671
x-Gentoo-Bug-URL: http://bugs.gentoo.org/391671
Reported-by: Duncan <1i5t5.duncan@cox.net>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

init.d/net.lo.in

@@ -144,7 +144,7 @@ _netmask2cidr()
 	local i= len=
 	local IFS=.
 	for i in $1; do
-		while [ i -ne 0 ]; do
+		while [ ${i} -ne 0 ]; do
 			: $(( len += i % 2 ))
 			: $(( i >>= 1 ))
 		done