[DBAL-139] Fix sequence cache assumptions.

lib/Doctrine/DBAL/Platforms/OraclePlatform.php

@@ -213,7 +213,7 @@ class OraclePlatform extends AbstractPlatform
         if ($sequence->getCache() === 0) {
             return ' NOCACHE';
         } else if ($sequence->getCache() === 1) {
-            return ' CACHE 20';
+            return ' NOCACHE';
         } else if ($sequence->getCache() > 1) {
             return ' CACHE ' . $sequence->getCache();
         }

tests/Doctrine/Tests/DBAL/Platforms/OraclePlatformTest.php

@@ -406,7 +406,7 @@ class OraclePlatformTest extends AbstractPlatformTestCase
     public function dataCreateSequenceWithCache()
     {
         return array(
-            array(1, 'CACHE 20'),
+            array(1, 'NOCACHE'),
             array(0, 'NOCACHE'),
             array(3, 'CACHE 3')
         );