Declare NODE_NAME environment variable

Undeclaring NODE_NAME parameter results in the wrong network
configuration used which will cause deploying failure when
deploying hosts. In this patch, "arm-virtual-host" will be
assigned to NODE_NAME for fixing this error.
At the same time, a bug in iec installation script was resolved.

Signed-off-by: Jingzhao.Ni <Jingzhao.Ni@arm.com>
Change-Id: I79b638cfa41e650e0c08e601a8efb7635922cca0