removed unused imports

Author: Anirav Kareddy

src/main/java/software/amazon/encryption/s3/internal/ContentMetadata.java

@@ -5,7 +5,6 @@
 import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
 import software.amazon.encryption.s3.algorithms.AlgorithmSuite;
 import software.amazon.encryption.s3.materials.EncryptedDataKey;
-import software.amazon.encryption.s3.materials.MaterialsDescription;
 
 import java.util.Collections;
 import java.util.Map;

src/main/java/software/amazon/encryption/s3/materials/S3Keyring.java

@@ -3,7 +3,6 @@
 package software.amazon.encryption.s3.materials;
 
 import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
-import software.amazon.encryption.s3.S3EncryptionClient;
 import software.amazon.encryption.s3.S3EncryptionClientException;
 
 import java.nio.charset.StandardCharsets;
@@ -14,8 +13,6 @@
 import java.util.Map;
 import javax.crypto.SecretKey;
 
-import org.apache.commons.logging.LogFactory;
-
 /**
  * This serves as the base class for all the keyrings in the S3 encryption client.
  * Shared functionality is all performed here.