Revert "pkg: advertising the root shell menu isn't useful"

This reverts commit 7030a38a.
Avoids a warning on bootup when done.  It may throw people off.

pkg/+POST_INSTALL

+echo "Updating /etc/shells"
+cp /etc/shells /etc/shells.bak
+(grep -v /usr/local/etc/rc.initial /etc/shells.bak; \
+    echo /usr/local/etc/rc.initial) > /etc/shells
+rm -f /etc/shells.bak
+
 echo "Registering root shell"
 pw usermod -n root -s /usr/local/etc/rc.initial
 

pkg/+PRE_DEINSTALL

 echo "Resetting root shell"
 pw usermod -n root -s /bin/csh
 
+echo "Updating /etc/shells"
+cp /etc/shells /etc/shells.bak
+(grep -v /usr/local/etc/rc.initial /etc/shells.bak) > /etc/shells
+rm -f /etc/shells.bak
+
 echo "Unhooking from /etc/rc"
 cp /etc/rc /etc/rc.bak
 tail -n +5 /etc/rc.bak > /etc/rc