Fix up the cleanup of the temporary DB so it works for BSD DB's

compatibility layer as well as "classic" ndbm.

Lib/test/test_dbm.py

@@ -28,7 +28,15 @@ d.close()
 
 try:
     import os
+    if dbm.library == "ndbm":
+        # classic dbm
         os.unlink(filename + '.dir')
         os.unlink(filename + '.pag')
+    elif dbm.library == "BSD db":
+        # BSD DB's compatibility layer
+        os.unlink(filename + '.db')
+    else:
+        # GNU gdbm compatibility layer
+        os.unlink(filename)
 except:
     pass