fix update to remove shares where file doesn't exist on postgres

Without patch, breaks with: Failed to upgrade "files_sharing".
Exception="SQLSTATE[22P02]: Invalid text representation: 7 ERROR:
invalid input syntax for integer: "5,179""

See: owncloud#5758

apps/files_sharing/appinfo/update.php

@@ -71,18 +71,7 @@
 
 // clean up oc_share table from files which are no longer exists
 if (version_compare($installedVersion, '0.3.5', '<')) {
-
-	// get all shares where the original file no longer exists
-	$findShares = \OC_DB::prepare('SELECT `file_source` FROM `*PREFIX*share` LEFT JOIN `*PREFIX*filecache` ON `file_source` = `*PREFIX*filecache`.`fileid` WHERE `*PREFIX*filecache`.`fileid` IS NULL AND `*PREFIX*share`.`item_type` IN (\'file\', \'folder\')');
-	$sharesFound = $findShares->execute(array())->fetchAll();
-
-	// delete those shares from the oc_share table
-	if (is_array($sharesFound) && !empty($sharesFound)) {
-		$delArray = array();
-		foreach ($sharesFound as $share) {
-			$delArray[] = $share['file_source'];
-		}
-		$removeShares = \OC_DB::prepare('DELETE FROM `*PREFIX*share` WHERE `file_source` IN (?)');
-		$result = $removeShares->execute(array(implode(',', $delArray)));
-	}
+	// delete all shares where the original file no longer exists
+	$removeShares = \OC_DB::prepare('DELETE FROM `*PREFIX*share` WHERE `file_source` IN (SELECT `file_source` FROM `*PREFIX*share` LEFT JOIN `*PREFIX*filecache` ON `file_source` = `*PREFIX*filecache`.`fileid` WHERE `*PREFIX*filecache`.`fileid` IS NULL AND `*PREFIX*share`.`item_type` IN (\'file\', \'folder\'))');
+	$result = $removeShares->execute(array(implode(',', $delArray)));
 }