CLOUDSTACK-287: don't allow API call against system account (adding users to system account is prohibited; can't delete/update System account)
CLOUDSTACK-287: don't allow API call against system account (adding users to system account is prohibited; can't delete/update System account)

Conflicts:

	server/src/com/cloud/user/AccountManagerImpl.java

mufaddalq/cloudstack-datera-driver,resmo/cloudstack,mufaddalq/cloudstack-datera-driver,jcshen007/cloudstack,GabrielBrascher/cloudstack,DaanHoogland/cloudstack,GabrielBrascher/cloudstack,mufaddalq/cloudstack-datera-driver,wido/cloudstack,wido/cloudstack,mufaddalq/cloudstack-datera-driver,resmo/cloudstack,mufaddalq/cloudstack-datera-driver,jcshen007/cloudstack,GabrielBrascher/cloudstack,resmo/cloudstack,resmo/cloudstack,wido/cloudstack,resmo/cloudstack,DaanHoogland/cloudstack,GabrielBrascher/cloudstack,resmo/cloudstack,DaanHoogland/cloudstack,GabrielBrascher/cloudstack,wido/cloudstack,DaanHoogland/cloudstack,jcshen007/cloudstack,wido/cloudstack,wido/cloudstack,DaanHoogland/cloudstack,GabrielBrascher/cloudstack,jcshen007/cloudstack,mufaddalq/cloudstack-datera-driver,resmo/cloudstack,jcshen007/cloudstack,jcshen007/cloudstack,DaanHoogland/cloudstack,DaanHoogland/cloudstack,wido/cloudstack,jcshen007/cloudstack,GabrielBrascher/cloudstack