Fix log library dependency conflict

Since we upgraded some of the infinispan components,

we now get in a basic spring-boot application this error on startup.

The dependency is coming by the test driver dependency that is picked up as "compile" scope today.

SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.SLF4J: Actual binding is of type [org.apache.logging.slf4j.Log4jLoggerFactory]Exception in thread "main" java.lang.ExceptionInInitializerError at org.springframework.boot.builder.SpringApplicationBuilder.createSpringApplication(SpringApplicationBuilder.java:109) at org.springframework.boot.builder.SpringApplicationBuilder.<init>(SpringApplicationBuilder.java:97) at org.infinispan.tutorial.simple.spring.session.UserSessionsApp.main(UserSessionsApp.java:12)Caused by: org.apache.logging.log4j.LoggingException: log4j-slf4j-impl cannot be present with log4j-to-slf4j