Fix shared storage namespace in DecryptAll class

lib/private/Encryption/DecryptAll.php

@@ -211,7 +211,7 @@ class DecryptAll {
 			$content = $this->rootView->getDirectoryContent($root);
 			foreach ($content as $file) {
 				// only decrypt files owned by the user
-				if($file->getStorage()->instanceOfStorage('OC\Files\Storage\Shared')) {
+				if($file->getStorage()->instanceOfStorage('OCA\Files_Sharing\SharedStorage')) {
 					continue;
 				}
 				$path = $root . '/' . $file['name'];

tests/lib/Encryption/DecryptAllTest.php

@@ -260,7 +260,7 @@ class DecryptAllTest extends TestCase {
 			->disableOriginalConstructor()->getMock();
 
 		$sharedStorage->expects($this->once())->method('instanceOfStorage')
-			->with('OC\Files\Storage\Shared')->willReturn(true);
+			->with('OCA\Files_Sharing\SharedStorage')->willReturn(true);
 
 		$this->view->expects($this->at(0))->method('getDirectoryContent')
 			->with('/user1/files')->willReturn(