__netbox_uwsgi: fix if only --bind-to given

If the here-document is empty because no file could be found, an empty
line will be read. The new line of code will skip in those cases.

type/__netbox_uwsgi/files/uwsgi.ini.sh

@@ -30,6 +30,8 @@ EOF
 
 # special protocol to bind
 while read -r param; do
+    if [ -z "$param" ]; then continue; fi  # ignore empty lines from the here-doc
+
     multi_options "$(basename "$param" | awk -F'-' '{print $1}')-socket" "$param"
     socket_changes="yes"