[checkupdates] UpdateCheckData tag for verocode if no regex

Use the tag as the version code if no regex was specified. This allows:

UpdateCheckData: '|||'

meaning the tag should be used for version code and name.

fdroidserver/checkupdates.py

@@ -171,11 +171,13 @@ def check_tags(app, pattern):
                 else:
                     filecontent = tag
 
-                m = re.search(codeex, filecontent)
-                if not m:
-                    continue
+                vercode = tag
+                if codeex:
+                    m = re.search(codeex, filecontent)
+                    if not m:
+                        continue
 
-                vercode = m.group(1).strip()
+                    vercode = m.group(1).strip()
 
                 if filever:
                     if filever != '.':

tests/checkupdates.TestCase

@@ -265,6 +265,13 @@ class CheckupdatesTest(unittest.TestCase):
             self.assertEqual(vername, '1.1.0')
             self.assertEqual(vercode, '1')
 
+        app.UpdateCheckData = '|||'
+        vcs.latesttags.return_value = ['2']
+        with mock.patch('fdroidserver.common.getvcs', return_value=vcs):
+            vername, vercode, _tag = fdroidserver.checkupdates.check_tags(app, None)
+            self.assertEqual(vername, '2')
+            self.assertEqual(vercode, '2')
+
 
 if __name__ == "__main__":
     parser = optparse.OptionParser()