vsys: Avoid uninitialised variable warning

Initialise the parms array to 0 so that we don't get warnings from
the compiler when we call syscall() using it.

Caught by coverity (#985949)

Change-Id: I134841bcb334d06146386e55ebfa38c7be993311
Reviewed-on: http://gerrit.openafs.org/9395
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>