Update sandag_abm.properties

A separate "base" socec file no longer needed.

src/main/resources/sandag_abm.properties

@@ -131,7 +131,6 @@ report.path = %project.folder%/report/
 ##############################################################################################################################################################################
 ## MGRA data file: this token is referred to in many UECs in additon to submodels like truck
 mgra.socec.file = input/mgra15_based_input${year}.csv
-mgra.socec.base.file = input/mgra15_based_input_${year}_base.csv
 cvm.emp.input.file = input/percent_of_establishments_by_luz_size_emp_cat.xlsx
 ## scenario year
 scenarioYear = ${year}