Removed app/code/core/Zend (#2861)

Author: fballiano

README.md

@@ -178,14 +178,18 @@ If your project uses OpenMage through composer then all dependencies will be man
 If you just extracted the release zip/tarball in your project's main folder then be sure to:
 - remove the old copy of aforementioned libraries from your project, you can do that with this command:
   ```bash
-  rm -rf lib/Cm lib/Credis lib/mcryptcompat lib/Pelago lib/phpseclib lib/Zend
+  rm -rf app/code/core/Zend lib/Cm lib/Credis lib/mcryptcompat lib/Pelago lib/phpseclib lib/Zend
   ```
 
-
 - download the new release zip file that is named `openmage-VERSIONNUMBER.zip`, this one is built to contain the `vendor`
   folder generated by composer, with all the dependencies in it
 - extract the zip file in your project's repository as you always did
 
+We also decided to remove our Zend_DB patches (that were stored in `app/code/core/Zend`) because they were very old and
+not compatible with the new implementations made by ZF1-Future, which is much more advanced and feature rich.
+This may generate a problem with `Zend_Db_Select' statements that do not use 'Zend_Db_Expr' to quote expressions.
+If you see SQL errors after upgrading please remember to check for this specific issue in your code.
+
 ### New Config Options
 
 - `admin/design/use_legacy_theme`