Only require spl-devel-kmod = %{version}

Only require spl-devel-kmod = %{version}

Commit f6fb7651a0d05b357dc179cc4853263ce15da6ed introduced the idea
of working builds which work correctly.  However, because the zfs-kmod
depends on a specific 'spl-devel-kmod = {version}-%{release}' package
and the release component is unique the dependency is never satisfied.

This requires line was introduced to ensure the correct version of the
spl is always used.  In this context only the version number is required
so the release component has been dropped to satisfy the dependency.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>