Remove SERVER_URL in reporting deploy job

Remove SERVER_URL in reporting deploy job

Since we improved the reporting deploy way, the SERVER_URL is set
to http://testresults.opnfv.org/reporting2 by default. So we don't
need to set it.

So we have to ways:
In CI:
    docker run -itd -p 8084:8000 opnfv/reporting:tag
Personal use:
    docker run -itd -p 8084:8000 -e SERVER_URL={server_ip}:8084 opnfv/reporting:tag
    (8084 is the port mapping, you can change it)

Change-Id: Ibe8adbb4601378d59d4d1fe6c7dd3266222c47d1
Signed-off-by: chenjiankun <chenjiankun1@huawei.com>