LU-5953 build: use installed OFED by default

LU-5953 build: use installed OFED by default

During LNET autoconf phase, if OFED installed and its devel headers
are available, default to use it instead of in-Kernel IB driver.

Also handle wrong case where OFED installed but not devel preventing
to build against OFED. Had to add new "patches" vs "kernel_patches"
dir name use in recent OFED versions and to avoid its check to
collide with inkernel-IB builds case.

Current OFED headers detection mechanism allow for non-standard
prefix but relies on "ofed_info" command and on "%prefix/openib"
link (both are ok for 1.5.x and 3.x versions), and should work
for both source and DKMS Lustre builds.

Test-Parameters: nettypes=o2ib
Signed-off-by: Bruno Faccini <bruno.faccini@intel.com>
Change-Id: I82639f8392d5fe707a3b1a1719d53ab937e918b5
Reviewed-on: http://review.whamcloud.com/12686
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>