[filesapp] Update image loader ImageCache.DB_VERSION

Due to issue 1152084 some users might have incorrectly EXIF orientated
JPEG thumbnails in their image loader cache. Update the image loader's
IDB cache version to reset (aka clear) the users image loader cache.

Bug: 1152084
Change-Id: I3fee9a406c10cca435227418310379cda4b25fac
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2569194Reviewed-by: Alex Danilo <adanilo@chromium.org>
Commit-Queue: Alex Danilo <adanilo@chromium.org>
Auto-Submit: Noel Gordon <noel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#833089}

ui/file_manager/image_loader/cache.js

@@ -27,7 +27,7 @@ ImageCache.DB_NAME = 'image-loader';
  * @type {number}
  * @const
  */
-ImageCache.DB_VERSION = 14;
+ImageCache.DB_VERSION = 15;
 
 /**
  * Memory limit for images data in bytes.