Add Log4j and SLF4J logging libraries to the test runtime classpath.

spring-session-data-geode/spring-session-data-geode.gradle

@@ -28,6 +28,9 @@ dependencies {
 	testCompile "org.springframework.data:spring-data-geode-test"
 	testCompile slf4jDependencies
 
+//	testRuntime "org.apache.logging.log4j:log4j-to-slf4j"
+//	testRuntime "ch.qos.logback:logback-classic"
+
 	integrationTestRuntime "org.springframework.shell:spring-shell"
 
 }