volser: Use the new IH_CREATE_INIT function

Use IH_CREATE_INIT when restoring volume data, so we don't open each
restored data file twice.

Reviewed-on: http://gerrit.openafs.org/9970
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>
(cherry picked from commit ba42758ce218e8985adc0129d0ee3ffa8690537f)

Change-Id: I01a0506fefce299aa7dc799e3ff494dfbeb2b894
Reviewed-on: http://gerrit.openafs.org/10178
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Mark Vitale <mvitale@sinenomine.net>
Reviewed-by: Andrew Deason <adeason@sinenomine.net>
Reviewed-by: Stephan Wiesand <stephan.wiesand@desy.de>