Add elfutils-libelf-devel dependency
Add elfutils-libelf-devel dependency

The 4.14 kernel now requires elfutils-libelf-devel.  Install it
on the Amazon builders which are using for kernel.org builds.

Signed-off-by: Brian Behlendorf <32d50ad1e384dcb9a5bf7e40fa470df5dabaf348@llnl.gov>

gmelikov/zfs-buildbot,gmelikov/zfs-buildbot,zfsonlinux/zfs-buildbot,zfsonlinux/zfs-buildbot