Better mocking of bucket existence check

Author: sbeimin

src/test/java/com/upplication/s3fs/util/AmazonS3ClientMock.java

@@ -639,7 +639,7 @@ public String getIdentifier() {
                 }
             }
         }catch (IOException e) {
-            throw new RuntimeException(e);
+			throw new AmazonS3Exception("Problem creating Acl", e);
         }
 
         return res;
@@ -1451,6 +1451,6 @@ public AmazonS3Waiters waiters() {
 
 	@Override
 	public boolean doesBucketExistV2(String bucketName) throws SdkClientException, AmazonServiceException {
-		return !"newer-bucket".equals(bucketName);
+		return Files.exists(base.resolve(bucketName));
 	}
 }