do not save plain-text ETag when encryption is requested

[harshavardhana]

Description

do not save plain-text ETag when encryption is requested

Motivation and Context

fixes an issue under bucket replication could cause
ETags for replicated SSE-S3 single-part PUT objects,
to fail as we would attempt a decryption while listing,
or stat() operation.

How to test this PR?

set -x

export CI=1

make || exit -1

killall -9 minio

rm -rf /tmp/xl/
mkdir -p /tmp/xl/1/ /tmp/xl/2/

export MINIO_KMS_SECRET_KEY="my-minio-key:OSMM+vkKUTCvQs9YL/CVMIMt43HFhkUpqJxTmGl6rYw="

NODES=4

args1=()
args2=()
for i in $(seq 1 $NODES); do
        args1+=("http://localhost:$((9000 + $i))/tmp/xl/1/$i ")
        args2+=("http://localhost:$((9100 + $i))/tmp/xl/2/$i ")
done

for i in $(seq 1 $NODES); do
        ./minio server --address "127.0.0.1:$((9000 + $i))" ${args1[@]} & # | tee /tmp/minio/node.$i &
        ./minio server --address "127.0.0.1:$((9100 + $i))" ${args2[@]} & # | tee /tmp/minio/node.$i &
done

sleep 10

./mc alias set myminio1 http://localhost:9001 minioadmin minioadmin
./mc alias set myminio2 http://localhost:9101 minioadmin minioadmin

sleep 1

./mc mb myminio1/testbucket/ --with-lock
./mc mb myminio2/testbucket/ --with-lock
./mc encrypt set sse-s3 my-minio-key myminio1/testbucket/
./mc encrypt set sse-s3 my-minio-key myminio2/testbucket/

./mc replicate add myminio1/testbucket --remote-bucket http://minioadmin:minioadmin@localhost:9101/testbucket --priority 1

sleep 1

./mc cp internal.tar myminio1/testbucket/dir/1.tar
./mc cp internal.tar myminio2/testbucket/dir/2.tar

sleep 1

./mc ls myminio1/testbucket/dir/

./mc ls myminio2/testbucket/dir/

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Optimization (provides speedup with no functional changes)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• Fixes a regression (If yes, please add commit-id or PR # here)
• Unit tests added/updated
• Internal documentation updated
• Create a documentation update request here

[poornas]

https://github.com/minio/minio/blob/master/cmd/object-handlers-common.go#L193
etagMatch should be considered true if it is sse-s3 and etag is empty to avoid re-replicating if there are timing issues

[vadmeste]

LGTM