recycle SharedFileInfo values in fileInfo

fileInfo is composed of data from sharing, however additional data is
pulled when sidebar opens, e.g. the size. Then, existing data is
overwritten by data from the other source (files). The data points that
would be lost are not dirty however and still used, so we keep them.

Signed-off-by: Arthur Schiwon <blizzz@arthur-schiwon.de>