Tighten spl dependency on spl-kmod

Make spl depend on the same version of spl-kmod, rather than on same or
better. When yum repository contains a number of versions the dependency
resolution breaks on trying to install non-latest version.

Signed-off-by: Cyril Plisko <cyril.plisko@mountall.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes zfsonlinux/zfs#1677
Retroactively fix bogus %changelog date

New versions of rpmbuild detect the invalid date which was added
incorrectly to the changelog.  To silence this noise fix it.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #306
Document SPL module parameters.

This is a first draft of a spl-module-parameters(5) man page. I have
just extracted the parameter name and its description with modinfo,
then checked the source what type it is and its default value.

This will need more work, preferably someone that actually know these
values and what to use them for.  Similar to zfsonlinux/zfs#1856, but
for the spl.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes zfsonlinux/zfs#1856
3525 persistent l2arc.

This patch add a CTASSERT macro for compile time assertion.

This macro makes the compile to spit "mixed definition and code"
warning, I can't find a way to avoid it.