fixed readme rendering bug.

when there existed a directory named like dicovery file for readme, it crashed trying to read it's content. We just skip them now

rhodecode/controllers/summary.py

@@ -51,6 +51,7 b' from rhodecode.lib.celerylib import run_'
 from rhodecode.lib.celerylib.tasks import get_commits_stats
 from rhodecode.lib.helpers import RepoPage
 from rhodecode.lib.compat import json, OrderedDict
+from rhodecode.lib.vcs.nodes import FileNode
 
 log = logging.getLogger(__name__)
 
@@ -197,6 +198,8 b' class SummaryController(BaseRepoControll'
                 for f in README_FILES:
                     try:
                         readme = cs.get_node(f)
+                        if not isinstance(readme, FileNode):
+                            continue
                         readme_file = f
                         readme_data = renderer.render(readme.content, f)
                         log.debug('Found readme %s' % readme_file)