1.0.59 released

Hi,

Here's a new release.

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FUJITA Tomonori (1):
      tgt 1.0.59

Sagi Grimberg (2):
      iser: Clear tasks free list when closing the connection
      iser: Fix wrong access to the session discovery mode

Teruaki Ishizaki (1):
      sheepdog: fix to update data_vdi_id after writing data object