Fix man/fill_template for waf clean

Signed-off-by: falkTX <falktx@falktx.com>

man/fill_template

@@ -2,7 +2,7 @@
 d=""
 [ -z "$SOURCE_DATE_EPOCH" ] || d=--date=@$SOURCE_DATE_EPOCH
 
-if [ "$2" == "True" ]; then
+if [ -n "$2" ] && [ "$2" = "True" ]; then
   for i in *.0 ; do
     sed -e "s/!VERSION!/${1}/g" -e "s/!DATE!/`date $d '+%B %Y'`/g" < ${i} > ${i%%0}1
   done