[OCIS][OC Storage] etags are not updated consistently on file operations

[dpakach]

The etags are updated inconsistently on some file operations. The etags are updated sometimes but are not updated other times.

As a result these tests fail intermittentely

• Deleting a folder on parents
  apiWebdavEtagPropagation1/deleteFileFolder.feature

• Deleting a file in public shared folder on parents
  apiWebdavEtagPropagation1/moveFileFolder.feature:171

• Deleting a folder in public shared folder on parents
  apiWebdavEtagPropagation1/moveFileFolder.feature:240

• moving a folder into a subfolder on parents
  apiWebdavEtagPropagation1/moveFileFolder.feature:97

• copying a file into a folder should change etags of parents
  apiWebdavEtagPropagation2/copyFileFolder.feature:24
  apiWebdavEtagPropagation2/copyFileFolder.feature:25
  apiWebdavEtagPropagation2/copyFileFolder.feature:45
  apiWebdavEtagPropagation2/copyFileFolder.feature:46
  apiWebdavEtagPropagation2/copyFileFolder.feature:67
  apiWebdavEtagPropagation2/copyFileFolder.feature:68
  apiWebdavEtagPropagation2/copyFileFolder.feature:93
  apiWebdavEtagPropagation2/copyFileFolder.feature:94
  apiWebdavEtagPropagation2/copyFileFolder.feature:120
  apiWebdavEtagPropagation2/copyFileFolder.feature:121

• creating a folder inside a folder should change etag of parent
  apiWebdavEtagPropagation2/createFolder.feature:22
  apiWebdavEtagPropagation2/createFolder.feature:23
  apiWebdavEtagPropagation2/createFolder.feature:92

• restoring a version should change etags on parents
  apiWebdavEtagPropagation2/restoreVersion.feature:10

• uploading a file inside a folder changes the etags of the parents
  apiWebdavEtagPropagation2/upload.feature:139
  apiWebdavEtagPropagation2/upload.feature:11

[kiranparajuli589]

closing in behalf of owncloud/ocis#4251