Fix small posting bug

User name may not always be filled out and that causes errors if not
set

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>

board/forms.py

@@ -46,7 +46,7 @@ class PostForm(ModelForm):
 
     def clean_name(self):
         name = self.cleaned_data["name"]
-        if "##" in name:
+        if name and "##" in name:
             name, password = [v.strip() for v in name.split("##", 1)]
             self.instance.tripcode = generate_tripcode(password)
         return name