Commit 2ee4e7da accidentally introduced two issues which only occur
when rebuilding the ZFS source rpm outside the ZFS build system.
1) The _dracutdir, _udevdir, and _udevruledir macros must be checked
using the 'undefined' keyword. This was just overlooked in the
patch review and does not cause a failure when using 'make pkg'
because the values are provided by the make target.
2) The default _udevruledir path included a typo.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #2310