remove use of Grease>>#doTransaction:

Author: pdebruic

repository/Zinc-HTTP.package/ZnSingleThreadedServer.class/instance/write.duringTransactionOn..st

@@ -0,0 +1,16 @@
+request handling
+write: response duringTransactionOn: stream
+  | commitResult |
+  System inTransaction
+    ifTrue: [ 
+      "We already are in a transaction, so just write the response"
+      response writeOn: stream.
+      ^ true ]
+    ifFalse: [ 
+      [ 
+      System beginTransaction.
+      response writeOn: stream ]
+        ensure: [ 
+          "workaround for Bug 42963: ensure: block executed twice (don't return from ensure: block)"
+          commitResult := System commitTransaction ] ].
+  ^ commitResult