SystemBase::n_vars() no longer asserts that the system has variables, so it will return 0 for a system in which no variables have been defined.
SystemBase::n_vars() no longer asserts that the system has variables, so it will return 0 for a system in which no variables have been defined.


git-svn-id: ffc1bc5b3feaf8644044862cc38c386ade156493@177 434f946d-2f3d-0410-ba4c-cb9f52fb0dbf

certik/libmesh,certik/libmesh,certik/libmesh,certik/libmesh,certik/libmesh,certik/libmesh,certik/libmesh