Correct misspelled words

In some files I found misspelling words.

bin/swift-reconciler-enqueue#l26
   primarly => primarily
swift/account/backend.py#l309
   ommited => omitted
swift/container/replicator.py#l158
   successfull => successful
test/unit/account/test_backend.py#1450
   non_existant_policy_index => non_existent_policy_index
test/unit/account/test_backend.py#1451
   'test-non-existant-policy'=> 'test-non-existent-policy'
test/unit/account/test_backend.py#1453
   non_existant_policy_index => non_existent_policy_index

Change-Id: I976236e3200a6fbdc20be464acff182b6cface81