mk: Don't touch config.tmp or tmp/dist as root. Closes #13190

When running `make install` we are touching these files that can't
then be removed later.

src/etc/install.sh

@@ -45,7 +45,6 @@ putvar() {
     else
         printf "install: %-20s := %s %s\n" $1 "$T" "$2"
     fi
-    printf "%-20s := %s\n" $1 "$T" >>config.tmp
 }
 
 valopt() {