Description of problem:
In the kvm-rt-cert scripts, we run rteval via a boot script. But now it is failing to run at boot time.

Version-Release number of selected component (if applicable):
rteval-2.9-1.el7_2.noarch
rteval-loads-1.3-3.el7.noarch
rteval-common-2.9-1.el7_2.noarch

How reproducible:
Always

Steps to Reproduce:

1. Add the following service:
------------------------- %< ----------------
# cat /usr/lib/systemd/system/kvm-rt-guest.service 
[Unit]
Description=Automated cyclictest run
After=tuned.service

[Service]
ExecStart=/usr/bin/load
TimeoutSec=0
RemainAfterExit=yes
WorkingDirectory=/root/bin
StandardOutput=tty
StandardError=tty

[Install]
WantedBy=multi-user.target
------------------------- >% ----------------

2. The following script and turn it executable:
-------------- %< -------------
# cat /usr/bin/load
#!/bin/sh

/usr/bin/rteval --onlyload --duration=1m --verbose
-------------- >% -------------

3. Enable the service:
# systemctl enable kvm-rt-guest

Reboot the box.


Actual results:

After the boot, rteval fails with the following message:
---------------- %< -------------------
    Traceback (most recent call last):
      File "/usr/bin/rteval", line 40, in <module>
        from rteval.Log import Log
      File "/usr/lib/python2.7/site-packages/rteval/__init__.py", line 37, in <module>
        from modules.loads import LoadModules
      File "/usr/lib/python2.7/site-packages/rteval/modules/__init__.py", line 26, in <module>
        from rteval.rtevalConfig import rtevalCfgSection
      File "/usr/lib/python2.7/site-packages/rteval/rtevalConfig.py", line 82, in <module>
        'srcdir'     : default_config_search(['loadsource']),
      File "/usr/lib/python2.7/site-packages/rteval/rtevalConfig.py", line 41, in default_config_search
        (os.getenv('SUDO_USER') or os.getenv('USER')) or ""), '.rteval'),
    TypeError: cannot concatenate 'str' and 'NoneType' objects
---------------- >% -------------------

Expected results:
No error messages

Additional info: