Remove unnecessary slf4j dependency

- causes problems for the logback appender tests
- also make the `logs` exchange consistent across all 3 appenders

Author: garyrussell

build.gradle

@@ -102,7 +102,6 @@ subprojects { subproject ->
 		mockitoVersion = '1.10.19'
 		rabbitmqVersion = project.hasProperty('rabbitmqVersion') ? project.rabbitmqVersion : '4.0.3'
 		rabbitmqHttpClientVersion = '1.1.1.RELEASE'
-		slf4jVersion = "1.7.25"
 
 		springVersion = project.hasProperty('springVersion') ? project.springVersion : '4.3.25.RELEASE'
 
@@ -131,7 +130,6 @@ subprojects { subproject ->
 			exclude group: 'org.hamcrest', module: 'hamcrest-core'
 		}
 		testCompile "org.springframework:spring-test:$springVersion"
-		testCompile "org.slf4j:slf4j-log4j12:$slf4jVersion" // amqp-client now uses SLF4J
 	}
 
 	// enable all compiler warnings; individual projects may customize further

spring-rabbit/src/test/resources/log4j-amqp.properties

@@ -12,7 +12,7 @@ log4j.appender.amqp.layout=org.apache.log4j.PatternLayout
 log4j.appender.amqp.layout.ConversionPattern=%d %p %t [%c] - <%m>%n
 log4j.appender.amqp.generateId=true
 log4j.appender.amqp.charset=UTF-8
-log4j.appender.amqp.durable=false
+log4j.appender.amqp.durable=true
 log4j.appender.amqp.deliveryMode=NON_PERSISTENT
 log4j.appender.amqp.declareExchange=true
 log4j.appender.amqp.clientConnectionProperties=foo:bar,baz:qux