Remove COPYING

There's no reason to keep this file around it's redundant with
the COPYRIGHT and OPENSOLARIS.LICENSE files and causes lintian
to emit an extra-license-file warning.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Change zfs-kmod-devel install path

Install the common zfs kernel development headers under
/usr/src/zfs-<version>/ rather than in a kernel specific
directory.  The kernel specific build products such as
zfs_config.h and Modules.symvers are left installed under
/usr/src/zfs-<version>/<kernel>.

This was done to be consistent with where dkms expects
kernel module source to be packaged.  It also allows for
a common zfs-kmod-devel package which includes the headers,
and per-kernel zfs-kmod-devel-<kernel> packages.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Configure --with-spl{-obj} auto-detect cleanup

Because the install location for the spl/zfs-devel headers was
changed we need to refresh the auto-detect code.  Note that
for packaging which already explicitly calls --with-spl{-obj}
nothing has changed.

The updated code is now structured like that in ZFS_AC_KERNEL
and should be cleaner and easier to maintain.  In addition,
it's stricter about detecting a valid source and object
directory.  It requires:

* The source directory contains the file 'spl.release'
* The object directory contains the file 'spl_config.h'
* The following paths will be checked.  Notice the /var/lib/
  and /usr/src paths require that the spl and zfs version be
  matched.  This is done to prevent accidentally mixing releases.

        dnl # 1) /var/lib/dkms/spl/<version>/build
        dnl # 2) /usr/src/spl-<version>/<kernel-version>
        dnl # 3) /usr/src/spl-<version>
        dnl # 4) ../spl
        dnl # 5) /usr/src/kernels/<kernel-version>

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

Refresh the existing RPM packaging to conform to the 'Fedora
Packaging Guidelines'.  This includes adopting the kmods2
packaging standard which is used fod kmods distributed by
rpmfusion for Fedora/RHEL.

  http://fedoraproject.org/wiki/Packaging:Guidelines
  http://rpmfusion.org/Packaging/KernelModules/Kmods2

While the spec files have been entirely rewritten from a
user perspective the only major changes are:

* The Fedora packages now have a build dependency on the
  rpmfusion repositories.  The generic kmod packages also
  have a new dependency on kmodtool-1.22 but it is bundled
  with the source rpm so no additional packages are needed.

* The kernel binary module packages have been renamed from
  zfs-modules-* to kmod-zfs-* as specificed by kmods2.

* The is now a common kmod-zfs-devel-* package in addition
  to the per-kernel devel packages.  The common package
  contains the development headers while the per-kernel
  package contains kernel specific build products.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1341
Add metaslab_debug option

Enabling metaslab debugging will prevent space maps from being
automatically unloaded.  This can significantly increase the
memory footprint but being able to dynamically control this is
helpful for debugging and certain performance testing.

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