fix: can't touch bytes_data with crc if not copying

Author: william-silversmith

mapbuffer/mapbuffer.py

@@ -288,7 +288,7 @@ def dict2buf(self, data, compress=None, tobytesfn=None):
     noop = lambda x: x
     tobytesfn = nvl(tobytesfn, self.tobytesfn, noop)
 
-    if tobytesfn == noop and compress is None:
+    if tobytesfn == noop and compress is None and not self.compute_crc:
       bytes_data = data
     else:
       bytes_data = {