Upgrade uwsgi and psyscopg2

Hopefully solves crashes on Heroku

requirements/production.txt

@@ -4,8 +4,8 @@
 elasticsearch==2.4.1
 # Additional dependencies for Heroku deployment
 dj-database-url==0.4.1
-uwsgi==2.0.17.1
-psycopg2==2.7.3.1
+uwsgi==2.0.18
+psycopg2==2.8.4
 whitenoise==3.2.2
 boto==2.45.0
 django-storages==1.6.5