Description of Problem: To make a long story short, I think line 77 of /sbin/ifdown should be changed from kill `cat /var/run/dhcpcd-${DEVICE}.pid` to kill -HUP `cat /var/run/dhcpcd-${DEVICE}.pid` Version-Release number of selected component (if applicable): 6.40-1
Note that the signal handling has changed somewhat in dhcpcd-1.3.21, so SIGHUP may no longer be necessary on normal reboot. I guess you should review the sources code in order to figure out what to do.
See bug 46942 for the reasoning here.