Treat LegacyVersion as InvalidVersion

This resolves a behavior difference with the packaging 21.3 version
on Leap 15.2 where parsing('1.7.40~svn') does not raise an
InvalidVersion exception but returns "<LegacyVersion('1.7.40~svn')>"
instead.

set_version

@@ -375,6 +375,9 @@ def _version_python_pip2rpm(version_pip):
 
     try:
         v = parse(version_pip)
+        with suppress(NameError):
+            if isinstance(v, LegacyVersion):
+                raise InvalidVersion
     except InvalidVersion:
         # Maybe is converted already?
         return None