fix parallel testing warning

Author: adamj34

tests/test_customizedbenders.py

@@ -228,6 +228,7 @@ def flpbenders_defcuts_test():
 
     master.printStatistics()
 
+    testbd.subprob.free()
     return master.getObjVal()
 
 def flpbenders_customcuts_test():
@@ -273,6 +274,7 @@ def flpbenders_customcuts_test():
 
     master.printStatistics()
 
+    testbd.subprob.free()
     return master.getObjVal()
 
 def flp_test():