Update hashes for prereqs that refer to pytz.

requirements/edx/custom.txt

@@ -10,7 +10,7 @@
 -e git+https://github.com/edx-solutions/xblock-adventure.git@effa22006bb6528bc6d3788787466eb4e74e1161#egg=xblock-adventure
 -e git+https://github.com/mckinseyacademy/xblock-poll.git@ca0e6eb4ef10c128d573c3cec015dcfee7984730#egg=xblock-poll
 -e git+https://github.com/OfficeDev/xblock-officemix/@86238f5968a08db005717dbddc346808f1ed3716#egg=xblock_officemix-master
--e git+https://github.com/edx/edx-notifications.git@4e3323da6775a101da5d8beab80c231278df69d2#egg=edx-notifications
+-e git+https://github.com/edx/edx-notifications.git@8038452f6fbb2b95ad46f8fe7a2f80b145b45b9c#egg=edx-notifications
 -e git+https://github.com/open-craft/problem-builder.git@f42c7c572c7c9e5155062f3f1874714abf63e92a#egg=problem-builder
 -e git+https://github.com/open-craft/xblock-group-project-v2.git@756d5e6456bb9090fe19b749d92e1d6560b6ba8b#egg=xblock-group-project-v2
 -e git+https://github.com/edx-solutions/xblock.git@80d11e883cb0f4b554e1e566294cb7de383cffed#egg=xblock

requirements/edx/github.txt

@@ -40,7 +40,7 @@ git+https://github.com/hmarr/django-debug-toolbar-mongo.git@b0686a76f1ce3532088c
 -e git+https://github.com/edx-solutions/django-splash.git@7579d052afcf474ece1239153cffe1c89935bc4f#egg=django-splash
 -e git+https://github.com/edx/acid-block.git@e46f9cda8a03e121a00c7e347084d142d22ebfb7#egg=acid-xblock
 -e git+https://github.com/edx/edx-ora2.git@release-2015-07-14T11.10#egg=edx-ora2
--e git+https://github.com/edx/edx-submissions.git@7c766502058e04bc9094e6cbe286e949794b80b3#egg=edx-submissions
+-e git+https://github.com/edx/edx-submissions.git@8b633d8dfa2040db0b0930dc53fca12290133d96#egg=edx-submissions
 -e git+https://github.com/edx/opaque-keys.git@df0dd602869e498e512659bb4bd243309e30e19a#egg=opaque-keys
 git+https://github.com/edx/ease.git@release-2015-07-14#egg=ease==0.1.3
 -e git+https://github.com/edx/i18n-tools.git@v0.1.1#egg=i18n-tools