Renamed --libstatedir to --statedir.

In BSD systems, it's usually </var/db> or some other dir under </var>
that is not </var/lib>, so $statedir is a more generic name.  See
hier(7).

Reported-by: Andrei Zeliankou <zelenkov@nginx.com>
Reported-by: Zhidao Hong <z.hong@f5.com>
Reviewed-by: Konstantin Pavlov <thresh@nginx.com>
Reviewed-by: Andrew Clayton <a.clayton@nginx.com>
Cc: Liam Crilly <liam@nginx.com>
Signed-off-by: Alejandro Colomar <alx@nginx.com>

tools/setup-unit

@@ -598,14 +598,14 @@ unit_ctl_welcome()
 
         # Check unitd is not configured already.
         echo "$cmd" \
-        | if grep '\--libstatedir' >/dev/null; then
+        | if grep '\--statedir' >/dev/null; then
             echo "$cmd" \
             | sed 's/ --/\n--/g' \
-            | grep '\--libstatedir' \
+            | grep '\--statedir' \
             | cut -d' ' -f2;
         else
             $cmd --help \
-            | sed -n '/\--libstatedir/,+1p' \
+            | sed -n '/\--statedir/,+1p' \
             | grep 'default:' \
             | sed 's/ *default: "\(.*\)"/\1/';
         fi \