CA-138822: Improvements to the Host/Pool Storage tab, following on from the TRIM work

- Show tooltip on "Reclaim freed space" button on multiselect

Signed-off-by: Mihaela Stoica <mihaela.stoica@citrix.com>
Merge pull request #130 from MihaelaStoica/CA-138822

CA-138822: Improvements to the Host/Pool Storage tab, following on from ...