Prevent from error when decoding key phrases

plugins/post_analysis/referers.py

@@ -112,7 +112,11 @@ class IWLAPostAnalysisReferers(IPlugin):
             groups = key_phrase_re.match(p)
             if groups:
                 key_phrase = groups.groupdict()['key_phrase']
+                try:
                     key_phrase = urllib.unquote_plus(key_phrase).decode('utf8')
+                except Exception, e:
+                    print(e)
+                    continue
                 if not key_phrase in key_phrases.keys():
                     key_phrases[key_phrase] = 1
                 else: