[master] Fix extracting GUID from ROOT files
At some point we upgraded to uproot 4 which now treats branch names as strings instead of binary data.
BEGINRELEASENOTES
*Core FIX: Fix extracting GUID from ROOT files with Python 3
ENDRELEASENOTES
At some point we upgraded to uproot 4 which now treats branch names as strings instead of binary data.
BEGINRELEASENOTES
*Core FIX: Fix extracting GUID from ROOT files with Python 3
ENDRELEASENOTES