Fix identity yaml parsing

Switch to sed rather than trying to use head.  There may or
may not be a second match, so need sed logic to understand
whether it's a match or not to keep or throw out.

confluent_osdeploy/coreos/initramfs/opt/confluent/bin/initconfluent.sh

@@ -12,7 +12,7 @@ if [ -e /dev/disk/by-label/CNFLNT_IDNT ]; then
     cd $tmnt
     deploysrvs=$(sed -n '/^deploy_servers:/, /^[^-]/p' cnflnt.yml |grep ^-|sed -e 's/^- //'|grep -v :)
     nodename=$(grep ^nodename: cnflnt.yml|awk '{print $2}')
-    sed -n '/^net_cfgs:/, /^[^- ]/p' cnflnt.yml |grep '^[ -]'|sed -n '/^-/, /^-/p'|head -n -1 | sed -e 's/^[- ]*//'> $tcfg
+    sed -n '/^net_cfgs:/, /^[^- ]/{/^[^- ]/!p}' cnflnt.yml |sed -n '/^-/, /^-/{/^-/!p}'| sed -e 's/^[- ]*//'> $tcfg
     autoconfigmethod=$(grep ^ipv4_method: $tcfg)
     autoconfigmethod=${autoconfigmethod#ipv4_method: }
     if [ "$autoconfigmethod" = "dhcp" ]; then