Bug 22634: Standardize table creation for stockrotation* tables in kohastructure.sql

The existing pattern is:
DROP TABLE IF EXISTS ...
CRATE TABLE

Stockrotation was using:
CREATE TABLE IF NOT EXISTS ...
which would not recreate the table in a database it's already
existing in possibly causing mismatches in table structure.

To test:
- Drop your database
- Run through the web installer
- Make sure there are no Database/SQL errors
- Makse sure the 4 stockrotation tables have been created

Signed-off-by: Frédéric Demians <f.demians@tamil.fr>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>

Signed-off-by: Nick Clemens <nick@bywatersolutions.com>

installer/data/mysql/kohastructure.sql

@@ -4272,7 +4272,8 @@ CREATE TABLE `circulation_rules` (
 -- Table structure for table `stockrotationrotas`
 --
 
-CREATE TABLE IF NOT EXISTS stockrotationrotas (
+DROP TABLE IF EXISTS stockrotationrotas;
+CREATE TABLE stockrotationrotas (
     rota_id int(11) auto_increment,         -- Stockrotation rota ID
     title varchar(100) NOT NULL,            -- Title for this rota
     description text NOT NULL,              -- Description for this rota
@@ -4285,7 +4286,8 @@ CREATE TABLE IF NOT EXISTS stockrotationrotas (
 -- Table structure for table `stockrotationstages`
 --
 
-CREATE TABLE IF NOT EXISTS stockrotationstages (
+DROP TABLE IF EXISTS stockrotationstages;
+CREATE TABLE stockrotationstages (
     stage_id int(11) auto_increment,     -- Unique stage ID
     position int(11) NOT NULL,           -- The position of this stage within its rota
     rota_id int(11) NOT NULL,            -- The rota this stage belongs to
@@ -4306,7 +4308,8 @@ CREATE TABLE IF NOT EXISTS stockrotationstages (
 -- Table structure for table `stockrotationitems`
 --
 
-CREATE TABLE IF NOT EXISTS stockrotationitems (
+DROP TABLE IF EXISTS stockrotationitems;
+CREATE TABLE stockrotationitems (
     itemnumber_id int(11) NOT NULL,         -- Itemnumber to link to a stage & rota
     stage_id int(11) NOT NULL,              -- stage ID to link the item to
     indemand tinyint(1) NOT NULL default 0, -- Should this item be skipped for rotation?