convert svn: minor improvement to tag detection.

The better way is probably to list the latest tags directory and
look up the last log message for each entry. This is surprisingly
annoying to do.

hgext/convert/subversion.py

@@ -532,6 +532,8 b' class convert_svn(converter_source):'
             orig_paths, revnum, author, date, message, pool = arg
             orig_paths = svn_paths(orig_paths)
             for path in orig_paths:
+                if not path.startswith('/tags/'):
+                    continue
                 ent = orig_paths[path]
                 source = ent.copyfrom_path
                 rev = ent.copyfrom_rev
@@ -540,7 +542,7 b' class convert_svn(converter_source):'
 
         start = self.revnum(self.head)
         try:
-            svn.ra.get_log(self.ra, ['/tags'], start, 0, 1, True, False,
+            svn.ra.get_log(self.ra, ['/tags'], 0, start, 0, True, False,
                            parselogentry)
             return tags
         except SubversionException: