Log File Parsing Fails When Last Logging Event is an Exception

[jujoramos]

Method readLastLine from AbstractLogParser doesn't take into consideration the actual log message format. If the last line of a log file belongs to a stack-trace, the subsequent parsing of the interval covered by the file will fail with java.lang.IllegalArgumentException: Parsing failed, no data available.
As an example, a file ending with the following logging event will always fail:

[warning 2016/12/12 10:00:00.000 BST server <ServerConnection on port 40404 Thread 10308> tid=0x6061] Server connection from [identity(XXXXXXX(XXXX:27260:loner):3:XXXXXX,connection=1; port=60917]: Unexpected IOException: 
java.net.SocketException: Connection reset
	at java.net.SocketInputStream.read(SocketInputStream.java:209)
	at java.net.SocketInputStream.read(SocketInputStream.java:141)
	at com.gemstone.gemfire.internal.cache.tier.sockets.Message.fetchHeader(Message.java:678)
	at com.gemstone.gemfire.internal.cache.tier.sockets.Message.readHeaderAndPayload(Message.java:702)
	at com.gemstone.gemfire.internal.cache.tier.sockets.Message.read(Message.java:645)
	at com.gemstone.gemfire.internal.cache.tier.sockets.Message.recv(Message.java:1142)
	at com.gemstone.gemfire.internal.cache.tier.sockets.Message.recv(Message.java:1156)
	at com.gemstone.gemfire.internal.cache.tier.sockets.BaseCommand.readRequest(BaseCommand.java:934)
	at com.gemstone.gemfire.internal.cache.tier.sockets.ServerConnection.doNormalMsg(ServerConnection.java:753)
	at com.gemstone.gemfire.internal.cache.tier.sockets.ServerConnection.doOneMessage(ServerConnection.java:930)
	at com.gemstone.gemfire.internal.cache.tier.sockets.ServerConnection.run(ServerConnection.java:1179)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at com.gemstone.gemfire.internal.cache.tier.sockets.AcceptorImpl$1$1.run(AcceptorImpl.java:555)
	at java.lang.Thread.run(Thread.java:745)