Update django-fsm.

requirements.txt

@@ -12,7 +12,7 @@ django-bleach==0.6.1
 django-countries==6.1.2
 django-extensions==2.2.9
 django-filter==2.2.0
-django-fsm==2.6.1
+django-fsm==2.7.0
 django-heroku==0.3.1
 django-hijack==2.1.10
 django-otp==0.7.5 # Temporarily pin to an older version, later breaks django-two-factor-auth.