(Re-)Disable SftpVersionsTest for Netty I/O service factory
<excludes>
<!-- TODO (SSHD-822) need some more research as to why this fails frequently on Netty -->
<exclude>**/AbstractCheckFileExtensionTest.java</exclude>
+ <exclude>**/SftpVersionsTest.java</exclude>
</excludes>
</configuration>
</execution>
