xen/xsm: Make p->policyvers be a local variable (ver) to shut up GCC 5.1.1 warnings.

xen/xsm: Make p->policyvers be a local variable (ver) to shut up GCC 5.1.1 warnings.

policydb.c: In function ‘user_read’:
policydb.c:1443:26: error: ‘buf[2]’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
         usrdatum->bounds = le32_to_cpu(buf[2]);
                          ^
cc1: all warnings being treated as errors

Which (as Andrew mentioned) is because GCC cannot assume
that 'p->policyvers' has the same value between checks.

We make it local, optimize the name to 'ver' and the warnings go away.
We also update another call site with this modification to
make it more inline with the rest of the functions.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>