Similar to bug 1032809 (for dhclient) the dracut dhclient-script.sh should set address lifetimes to the DHCP lease time, so that other stuff (like NetworkManager!) knows that the address is temporary and was created by DHCP.  

This should be as simple as something like this (untested):

diff -up dracut-034/modules.d/40network/dhclient-script.sh.foo dracut-034/modules.d/40network/dhclient-script.sh
--- dracut-034/modules.d/40network/dhclient-script.sh.foo	2014-01-27 18:36:33.965704565 -0600
+++ dracut-034/modules.d/40network/dhclient-script.sh	2014-01-27 18:40:04.528072174 -0600
@@ -12,6 +12,7 @@ setup_interface() {
     search=$(printf -- "$new_domain_search")
     namesrv=$new_domain_name_servers
     hostname=$new_host_name
+    lease_time=$new_dhcp_lease_time
 
     [ -f /tmp/net.$netif.override ] && . /tmp/net.$netif.override
 
@@ -29,7 +30,9 @@ setup_interface() {
         fi
     fi
 
-    ip addr add $ip${mask:+/$mask} ${bcast:+broadcast $bcast} dev $netif
+    ip addr add $ip${mask:+/$mask} ${bcast:+broadcast $bcast} \
+        valid_lft ${lease_time} preferred_lft ${lease_time} \
+        dev $netif
 
     [ -n "$gw" ] && echo ip route add default via $gw dev $netif > /tmp/net.$netif.gw
 

and will result in 'ip addr' showing the correct valid_lft and preferred_lft instead of "forever", which they clearly are not valid for.

Thanks!