Modify gethrestime to use current_kernel_time()

This allows us to get nanosecond resolution. It also means
we use the same time source as utimensat(now) etc.

Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #255
Merge branch 'upstream' into snapshot/ubuntu/saucy
Use the deb revision instead of the META release.

If ZoL is built from a git clone, then the current commit hash is put
into the Release field of the META file.

Do the same thing, but for GBP snapshot builds and PPA releases.
Update changelog for 0.6.1-2~saucy~3.gbpb960c9 release