Revert "Changed optional nominations_accepted field to have blank=True"
Revert "Changed optional nominations_accepted field to have blank=True"

This reverts commit 76f1a303e6f342595475c1c1c1c3dd9609b51571.

deepankverma/badges.mozilla.org,mozilla/badges.mozilla.org,deepankverma/badges.mozilla.org,mozilla/badges.mozilla.org,mozilla/badges.mozilla.org,deepankverma/badges.mozilla.org,mozilla/badges.mozilla.org,deepankverma/badges.mozilla.org