Allow regenerating random story using Retry button

Commit b55e5a8e0b removed this feature, so
this commit adds it back.

aiserver.py

@@ -2862,6 +2862,9 @@ def actionretry(data):
     if(vars.noai):
         emit('from_server', {'cmd': 'errmsg', 'data': "Retry function unavailable in Read Only mode."})
         return
+    if(vars.recentrng is not None):
+        randomGameRequest(vars.recentrng, memory=vars.recentrngm)
+        return
     if actionback():
         actionsubmit("", actionmode=vars.actionmode, force_submit=True)
         send_debug()