wrap seafile-server-tools to use python dependencies

- also fix seahub dependencies

seafile-server/django-version.patch

@@ -0,0 +1,18 @@
+diff --git a/tools/seafile-admin b/tools/seafile-admin
+index 5e3658b..2fc2c08 100755
+--- a/tools/seafile-admin
++++ b/tools/seafile-admin
+@@ -518,10 +518,10 @@ def init_seahub():
+ 
+ 
+ def check_django_version():
+-    '''Requires django 1.8'''
++    '''Requires django 1.11 or later'''
+     import django
+-    if django.VERSION[0] != 1 or django.VERSION[1] != 8:
+-        error('Django 1.8 is required')
++    if django.VERSION[0] != 1 or django.VERSION[1] < 11:
++        error('Django 1.11+ is required')
+     del django
+ 
+