man un-diverting man idempotent

debian/changelog

@@ -1,4 +1,4 @@
-livecd-rootfs (2.529~ppa4) cosmic; urgency=medium
+livecd-rootfs (2.529~ppa6) cosmic; urgency=medium
 
   * Improvements to the ubuntu-base (i.e. Docker) build:
     - Customize the unminimize script to not install ubuntu-minimal.

live-build/auto/build

@@ -115,7 +115,7 @@ echo ""
 echo "Reinstallation of packages may fail due to changes to the system"
 echo "configuration, the presence of third-party packages, or for other"
 echo "reasons."
-read -p "Would you like to continue? [y/N]" REPLY
+read -p "Would you like to continue? [y/N] " REPLY
 echo    # (optional) move to a new line
 if [ "$REPLY" != "y" ] && [ "$REPLY" != "Y" ]
 then
@@ -153,9 +153,11 @@ if [ -f /etc/dpkg/dpkg.cfg.d/excludes ] || [ -f /etc/dpkg/dpkg.cfg.d/excludes.dp
     fi
 fi
 
-# Remove diverted man binary
-rm -f /usr/bin/man
-dpkg-divert --quiet --remove --rename /usr/bin/man
+if  [ "$(dpkg-divert --truename /usr/bin/man)" = "/usr/bin/man.REAL" ]; then
+    # Remove diverted man binary
+    rm -f /usr/bin/man
+    dpkg-divert --quiet --remove --rename /usr/bin/man
+fi
 EOF
 
                 if [ "$PROJECT" != "ubuntu-base" ]; then