_introspect_all_indexes can break during GSI deletion

[jseakle]

This block expects the 'Projection' field to exist in each index, but when the index has the "DELETING" status (or similar, I can no longer quickly find the actual status string), this field is not present, causing a KeyError. We luckily discovered this in testing, but were at significant risk of having it impact a production system.

We've worked around it by monkey-patching the function to add

    try:
        field['Projection']
        field['Projection']['ProjectionType']
    except KeyError:
        continue

but this is of course brittle and undesirable.

[Stas Alekseev]

+1