bump dependency versions, fix tests and deprecation warnings

gnuviechadmin/managemails/admin.py

@@ -1,7 +1,7 @@
 from django.utils.html import format_html
 from django.contrib import admin
 from django import forms
-from django.forms.util import flatatt
+from django.forms.utils import flatatt
 from django.utils.translation import ugettext as _
 
 from .models import (

gnuviechadmin/osusers/models.py

@@ -533,7 +533,10 @@ class SshPublicKeyManager(models.Manager):
                 raise ValueError('invalid SSH public key')
             data = parts[1]
             comment = len(parts) == 3 and parts[2] or ""
-        keybytes = base64.b64decode(data)
+        try:
+            keybytes = base64.b64decode(data)
+        except TypeError:
+            raise ValueError('invalid SSH public key')
         parts = keybytes.split(b'\x00' * 3)
         alglength = six.byte2int(parts[1])
         algname = parts[1][1:1+alglength]