Use the standard Linux MODULE_VERSION macro to expose the installed
zavl, znvpair, zunicode, zcommon, zfs, and zpios module versions.
This will also automatically add a checksum of the .c files and
headers in "srcversion". See:
/sys/module/zavl/version
/sys/module/zavl/srcversion
/sys/module/znvpair/version
/sys/module/znvpair/srcversion
/sys/module/zunicode/version
/sys/module/zunicode/srcversion
/sys/module/zcommon/version
/sys/module/zcommon/srcversion
/sys/module/zfs/version
/sys/module/zfs/srcversion
/sys/module/zpios/version
/sys/module/zpios/srcversion
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1923