importer: Actually perform the Spamhaus sanity check

The check block was indented incorrectly and would have never been
executed.
Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>

src/scripts/location-importer.in

@@ -1402,6 +1402,7 @@ class CLI(object):
 				""")
 			else:
 				log.error("Spamhaus DROP URL %s returned likely bogus file, ignored" % url)
+				continue
 
 			# Iterate through every line, filter comments and add remaining networks to
 			# the override table in case they are valid...