Description of problem:
I think Condor should prevent to change classads which should not be changed. 
Now Condor does not allow change some classads, for example ClusterID:
$ condor_qedit 20.0 ClusterID 300
Failed to set attribute "ClusterID" for job 20.0.

the same does Aviary:
mrg_utils.MRGException: u'Aviary query error(FAIL): Failed to set attribute ClusterID to 300'

But Aviary and QMF have different internal structures, so they have different list of classads which should not be modified.

I think QMF plugins, Aviary and condor_qedit should prevent changing of classads which are part of QMF, Aviary and Condor system structures.

Example of classad which is part of internal structure - "Submission": bug 705016


Version-Release number of selected component (if applicable):
condor-7.6.1-0.4.el6.i686
condor-aviary-7.6.1-0.4.el6.i686
condor-classads-7.6.1-0.4.el6.i686
condor-debuginfo-7.6.1-0.4.el6.i686
condor-qmf-7.6.1-0.4.el6.i686
condor-wallaby-base-db-1.12-1.el6.noarch
condor-wallaby-client-4.0-6.el6.noarch
condor-wallaby-tools-4.0-6.el6.noarch
python-condorutils-1.5-3.el6.noarch
python-qpid-qmf-0.10-6.el6.i686
qpid-qmf-0.10-6.el6.i686
ruby-qpid-qmf-0.10-6.el6.i686
wso2-axis2-2.1.0-3.el6.i686
wso2-rampart-2.1.0-3.el6.i686
wso2-wsf-cpp-2.1.0-3.el6.i686
wso2-wsf-cpp-debuginfo-2.1.0-3.el6.i686