Fixed missing dependency to slf4j

connector-service/build.gradle

@@ -23,11 +23,11 @@ dependencies {
 	compile group: 'org.hsqldb', name: 'hsqldb', version: '2.2+'
 	compile group: 'cglib', name: 'cglib', version: '3.0+'
 	compile group: 'de.thm.arsnova.connector', name: 'connector-model', version: '0.+'
-	compile group: 'de.thm.arsnova.connector', name: 'connector-client', version: '0.+'
 
 	testCompile group: 'junit', name: 'junit', version: '4.+'
 	testCompile group: 'org.mockito', name: 'mockito-core', version: '1.9.+'
 	testCompile group: 'org.dbunit', name: 'dbunit', version: '2.4.+'
+	testCompile group: 'org.slf4j', name: 'slf4j-log4j12', version: '1.5.6'
 }
 
 test { systemProperties 'property': 'value' }