Allow HG patch to appear late in the input stream

mercurial/commands.py

@@ -740,6 +740,7 b' def import_(ui, repo, patch1, *patches, '
                     hgpatch = False
             elif line == '# HG changeset patch':
                 hgpatch = True
+                message = []       # We may have collected garbage
             else:
                 message.append(line)