LU-14588 o2ib: make config script aware of the ofed symbols

LU-14588 o2ib: make config script aware of the ofed symbols

LNet o2ib configuration script needs to be aware of the external
ofed dkms symbols when testing for availability of o2ib features
by building "conftest" kernel objects. If this is not done,
symbols from the core kernel are used by default which is
different from what is used when actually building LNet,
at least on Ubuntu. This patch adds the check for external symbols.

Test-Parameters: trivial
Signed-off-by: Serguei Smirnov <ssmirnov@whamcloud.com>
Change-Id: Iea566f8a3feb86b8bef2f4501a3abc968d76451a
Reviewed-on: https://review.whamcloud.com/43223
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Amir Shehata <ashehata@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>