export: Fix generating file names for ipset output

The tag that is being used in the filename was set after creating the
filename. The order has now been fixed and the export works fine for me.

Fixes: #12944
Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>

src/python/location/export.py

@@ -48,6 +48,9 @@ class OutputWriter(object):
 		self.family = family
 		self.directory = directory
 
+		# Tag
+		self.tag = self._make_tag()
+
 		# Open output file
 		if f:
 			self.f = f
@@ -58,9 +61,6 @@ class OutputWriter(object):
 		else:
 			self.f = io.StringIO()
 
-		# Tag
-		self.tag = self._make_tag()
-
 		# Call any custom initialization
 		self.init()