I/O exception during send should include more than just 'null' in the UftpSendException message

[tomwetjens]

Expected:

org.lfenergy.shapeshifter.core.service.sending.UftpSendException: Unexpected I/O exception while sending UFTP message to <endpoint>: java.net.ConnectException: null

Actual:

org.lfenergy.shapeshifter.core.service.sending.UftpSendException: Unexpected I/O exception while sending UFTP message to <endpoint>: null
	at org.lfenergy.shapeshifter.core.service.sending.UftpSendMessageService.send(UftpSendMessageService.java:169) ~[shapeshifter-core-2.4.0.jar:na]
	at org.lfenergy.shapeshifter.core.service.sending.UftpSendMessageService.send(UftpSendMessageService.java:130) ~[shapeshifter-core-2.4.0.jar:na]
	at org.lfenergy.shapeshifter.core.service.sending.UftpSendMessageService.doSend(UftpSendMessageService.java:119) ~[shapeshifter-core-2.4.0.jar:na]
	at org.lfenergy.shapeshifter.core.service.sending.UftpSendMessageService.attemptToSendMessage(UftpSendMessageService.java:97) ~[shapeshifter-core-2.4.0.jar:na]