benchmark: Install IB in final dir not in source...

Stupid mistake not to install the IB stuff in the proper directory.
SRC was base dir while we are supposed to install it in the final dir
aka benchmark.
common: libmlx4 backport for Ubuntu precise

While using the verbs under Ubuntu precise, I had the following
behavior :

root@hpbig2:~# ibv_devices
libibverbs: Warning: no userspace device-specific driver found for /sys/class/infiniband_verbs/uverbs0
    device                 node GUID
    ------              ----------------
root@hpbig2:~#

As per https://bugs.launchpad.net/ubuntu/+source/libmlx4/+bug/1037107, and at the day of today,
the only solution we have is to install a package from quantal.

This is clearly weird to install a package this way but it makes verbs working as :

root@hpbig2:~# ibv_devices
    device                 node GUID
    ------              ----------------
    mlx4_0              0002c90300ea6820
root@hpbig2:~#

So this patch is taking the binary package and install it to the dest if we run a Ubuntu Precise.