Fix memory leaks in parallel runs

There is a small fix for the old parallel runs (removal of code from dp_vif.c that was already allocated on all processors with tran_alloc()

Another small fix to free data with an early exit in mm_shell_util.c

The rest are memory leaks caused by the brkfix integration.

The second commit is a little more ugly as it saves and restores a pointer to the global variable Element_Blocks as this is allocated every time rd_exo is called and brking and fixing need to use rd_exo and then free the Element_Blocks struct that was allocated for them.

Taking a closer look at the exodus structures and related functions might be a good idea because it looks like some of the data that is being read/written/created for exodus files is no longer being used by goma and not necessarily needed for the exodus file itself.

Also removes unneeded brkfix/exo_struct.h

Passes test suite, and parallel problems with new brk format.