Use 'git describe' for working builds

When building from an arbitrary commit in the git tree it's useful
for the resulting packages to be uniquely identifiable.  Therefore,
the build system has been updated to detect if your compiling in
git tree.

If you are building in a git tree, and there are commits after the
last annotated tag.  Then the <id>-<hash> component of 'git describe'
will be used to overwrite the 'Release:' field in the META file.

The only tricky part is that to ensure the 'make dist' tarball is
built using the correct release.  A dist-hook was added to the top
level make file to rewrite the META file using the correct release.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Provide ${kmodname}-devel-kmod for yum-builddep

In order to ensure that yum-builddep pulls in all the build
requirements a generic ${kmodname}-devel-kmod provides line is
added.  This allows a version of the development headers to be
included without requiring knowledge of the kernel version.

This is important because unlike rpmbuild which does correctly
expand the source rpm spec file, yum-builddep does not.  Without
this generic provides line mock which relies on yum-builddep is
unable to automatically satisfy the dependency.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Include init scripts in packages

The distribution specific init scripts where excluded from the
packaging when it was reworked.  The intention is to replace
them with systemd equivilants.  However, that work has not yet
been done and the init scripts are still useful so they have
been added back in to the packaging.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Tag zfs-0.6.1

META file and release log updated.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Merge with origin/master.
Merge branch 'master' of git://github.com/zfsonlinux/zfs into iscsi