Bugfix: two or more default routes with metric 0

This commit fixes the following bug:
When two or more default routes with metric 0 where in place, the update-status
hook fails to check that the default gateway is correctly set.

hooks/update-status

@@ -18,7 +18,7 @@ GATEWAY_IP="$( echo "$GATEWAY" | awk -F "/" '{print $1}' )"
 
 DEFAULTROUTECOMMAND="$( getdefaultroutecommand )"
 
-if eval $DEFAULTROUTECOMMAND | grep "\<${GATEWAY_IP}\>"; then
+if [ $(eval $DEFAULTROUTECOMMAND | wc -l ) -eq 1 ] && eval $DEFAULTROUTECOMMAND | grep "\<${GATEWAY_IP}\>"; then
     juju-log "Default gateway looks OK. Doing nothing."
     exit 0
 fi