Close IFormatReader copy if not to be used

The generated copy from Memoizer's loadReader logic
was in some cases not being used. When the null was
returned, a RandomAccessFile held by the reader was
left open.
merge dev_5_0 -D org: PR 1188 (AFI: populate magnification and physical pixel size metadata (rebased from develop))
merge dev_5_0 -D org: PR 1196 (Close IFormatReader copy if not to be used)
merge dev_5_0 -D org

Repository: openmicroscopy/bioformats
Already up-to-date.

Merged PRs:
  # PR 1188 mtbc 'AFI: populate magnification and physical pixel size metadata (rebased from develop)'
  # PR 1196 joshmoore 'Close IFormatReader copy if not to be used'
Generated by OMERO-5.0-merge-push#84 (http://ci.openmicroscopy.org/job/OMERO-5.0-merge-push/84/)