LU-2710 build: avoid function resolution mistakes by Coverity

LU-2710 build: avoid function resolution mistakes by Coverity

Remove function resolution mistakes made by Coverity version
6.0.3.
The .hs_keycmp function is incorrectly resolved by Coverity,
making the variable passed as its first 'key' parameter to
be considered of the wrong type. Data structures being of
different sizes, it ends up with this Coverity defect:
Out-of-bounds access (OVERRUN_STATIC)
Overrunning static array by passing it as an argument to a
function which indexes it at a higher byte position.

Signed-off-by: Sebastien Buisson <sebastien.buisson@bull.net>
Change-Id: Ie062b05a73db16d63c63db89dc4d0e264f3b1f8a
Reviewed-on: http://review.whamcloud.com/5211
Tested-by: Hudson
Reviewed-by: Keith Mannthey <keith.mannthey@intel.com>
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>