Remove workarounds for two ROOT6 bugs that were fixed

This pull request removes workaronds for two ROOT6 bugs that were fixed a while back.
This request reverts the two affected files to what they are in the 7_1_X branch.
The two ROOT6 bugs fixed were:
1) Infinite recursion of function calls if there is a persistent data member that is a container of (unsigned) long long.
2) Exceptions thrown if some transient data members did not have default constructors.
This request:
1) reverts long to long long
2) Removes the unnecessary default constructors.
Tested against the short relval matrix.  No changes observed.