Make binaries report udev version compatibility version instead of eudev version

Software such as dracut performs a sanity check on udev by querying the
udev tools for the version. Reporting the eudev version causes this
check to fail, so we resort to reporting the udev compatibility
versionj.

Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Ian Stakenvicius <axs@gentoo.org>
Merge pull request #39 from gentoo/udev-compatibility

Make binaries report udev version compatibility version instead of eudev...