ServletContainerInitializerDeploymentProcessor does not handle comments

ServletContainerInitializerDeploymentProcessor.loadSci() has code to read the service file, rather than using the JDK-provided mechanisms, and it does not handle comments.

The API documentation at https://docs.oracle.com/javase/7/docs/api/java/util/ServiceLoader.html says that the # symbols and all following characters on the line should be ignored. It also notes the file must be UTF-8 encoded, and ServletContainerInitializerDeploymentProcessor does not appear to force that either.

Log4j 2.1 triggers this bug (https://issues.apache.org/jira/browse/LOG4J2-890)