Some Fixes and Improvements

* Fix several typos in log messages. And some test on the matter as well
* Add comment to `AbstractPersistentAcceptOnceFileListFilter.rollback()` to clarify the reason of `rollingBack` variable
* Make `RemoteFileTemplate.StreamHolder` as `static` to avoid extra internal variable to outer class instance
* Replace `MessagingException` with `AbstractInboundFileSynchronizingMessageSource` in `init()` method of some components. It isn't Messaging yet in that phase
* Fix `SubscribableRedisChannel.MessageListenerDelegate` to handle `Object` not `String`, because with the `serializer` injection there is no guaranty that incoming is always `String`
* Move `JSch.setLogger(new JschLogger());` in the `DefaultSftpSessionFactory` to `static` block. It really should be done only once
* Remove `Assert.isTrue(this.port >= 0)` from the `DefaultSftpSessionFactory`. The subsequant `initJschSession()` convert it to default `22` port
* Change in the `JschProxyFactoryBean` `UnsupportedOperationException` to `IllegalArgumentException`. Wrong enum is wrong argument. That isn't a problem of operation
* Simplify `stop()` in the `CuratorFrameworkFactoryBean` and mark it as a `this.running = false`. Otherwise it wasn't able to be restarted
* Expose `leaderEventPublisher` in the `LeaderInitiatorFactoryBean`  and fix `stop(Runnable callback)` with propagation `callback` to delegate.

Fix `SubscribableRedisChannelTests` for new `handleMessage(Object)` signature

spring-integration-syslog/src/main/java/org/springframework/integration/syslog/config/SyslogReceivingChannelAdapterFactoryBean.java

@@ -181,7 +181,7 @@ public class SyslogReceivingChannelAdapterFactoryBean extends AbstractFactoryBea
 			else if (this.applicationEventPublisher != null) {
 				((TcpSyslogReceivingChannelAdapter) adapter).setApplicationEventPublisher(this.applicationEventPublisher);
 			}
-			Assert.isNull(this.udpAdapter, "Cannot specifiy 'udp-attributes' when the protocol is 'tcp'");
+			Assert.isNull(this.udpAdapter, "Cannot specify 'udp-attributes' when the protocol is 'tcp'");
 		}
 		else if (this.protocol == Protocol.udp) {
 			adapter = new UdpSyslogReceivingChannelAdapter();
@@ -189,7 +189,7 @@ public class SyslogReceivingChannelAdapterFactoryBean extends AbstractFactoryBea
 				Assert.isNull(this.port, "Cannot specify both 'port' and 'udpAdapter'");
 				((UdpSyslogReceivingChannelAdapter) adapter).setUdpAdapter(this.udpAdapter);
 			}
-			Assert.isNull(this.connectionFactory, "Cannot specifiy 'connection-factory' unless the protocol is 'tcp'");
+			Assert.isNull(this.connectionFactory, "Cannot specify 'connection-factory' unless the protocol is 'tcp'");
 		}
 		else {
 			throw new IllegalStateException("Unsupported protocol: " + this.protocol.toString());

spring-integration-syslog/src/test/java/org/springframework/integration/syslog/config/SyslogReceivingChannelAdapterParserTests.java

@@ -196,7 +196,7 @@ public class SyslogReceivingChannelAdapterParserTests {
 		catch (BeanCreationException e) {
 			e.printStackTrace();
 
-			assertEquals("Cannot specifiy 'udp-attributes' when the protocol is 'tcp'", e.getCause().getMessage());
+			assertEquals("Cannot specify 'udp-attributes' when the protocol is 'tcp'", e.getCause().getMessage());
 		}
 	}
 
@@ -208,7 +208,7 @@ public class SyslogReceivingChannelAdapterParserTests {
 			fail("Expected exception");
 		}
 		catch (BeanCreationException e) {
-			assertEquals("Cannot specifiy 'connection-factory' unless the protocol is 'tcp'",
+			assertEquals("Cannot specify 'connection-factory' unless the protocol is 'tcp'",
 					e.getCause().getMessage());
 		}
 	}