Windows: vol-salvage SalvInfo fixes

Windows: vol-salvage SalvInfo fixes

Commit 3d7388b790ef21de552ec60d379764df067ae421 broke the windows
build. Fix it:

 - SVGParms_t has no salvinfo member, but an svgp_salvinfo member

 - Correct the SalvageVolumeGroup prototype to match the actual
   implementation

Reviewed-on: http://gerrit.openafs.org/2595
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Tested-by: Derrick Brashear <shadow@dementia.org>
(cherry picked from commit 87dc2a312ac94bc0a8b809a8f879128be8d9c791)

Change-Id: I8fd13e683060ae4ae4818a03626e95680cc3e86d
Reviewed-on: http://gerrit.openafs.org/4176
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementia.org>