Upgrade django==1.11 mezzanine==4.3.1

diff --git a/lib/mezzanine b/lib/mezzanine
index 1ec7ffd5e26064a284eaeafb26ec45e383e3157c..961a2a15ee0eee431c85da717531db3de1cd7f84 160000 (submodule)
--- a/lib/mezzanine
+++ b/lib/mezzanine
@@ -1 +1 @@
-Subproject commit 1ec7ffd5e26064a284eaeafb26ec45e383e3157c
+Subproject commit 961a2a15ee0eee431c85da717531db3de1cd7f84

diff --git a/lib/mezzanine-organization b/lib/mezzanine-organization
index 24a94f3a647202f10e26bdea6c59c4f553b11bf8..51d24fc04580ac5807ff98c8d89ecf816bf3ad53 160000 (submodule)
--- a/lib/mezzanine-organization
+++ b/lib/mezzanine-organization
@@ -1 +1 @@
-Subproject commit 24a94f3a647202f10e26bdea6c59c4f553b11bf8
+Subproject commit 51d24fc04580ac5807ff98c8d89ecf816bf3ad53