[bsc] remove 1.3-only options by default

dysnix/bsc/values.yaml

@@ -113,11 +113,13 @@ bsc:
     value: 8192
     preimages: true
   state:
-    # possible options are "hash" and "path"(1.3.x+)
-    scheme: hash
+    # possible options (1.3.x+) are "hash" and "path"
+    # use empty value for 1.2.x
+    scheme: ""
   db:
-    # possible options are "leveldb" and "pebble"(1.3.x+)
-    engine: leveldb
+    # possible options (1.3.x+) are "leveldb" and "pebble"
+    # use empty value for 1.2.x
+    engine: ""
   txlookuplimit: 0                        # WARNING: won't work on BSC >=1.3.x, node will crash if it's provided. use ".Values.history.transactions" instead
   history:
     transactions: null                    # BSC >=1.3.x only