LU-13787 build: fix snmp / libcfs build order

LU-13787 build: fix snmp / libcfs build order

The Lustre snmp code is dependent on libcfs so make
sure libcfs is built first. This only shows up in
parallel builds.

Fixes: 742897a967cf ("LU-13274 uapi: make lnet UAPI headers C99 compliant")
Test-Parameters: trivial
Change-Id: Ibe1669e8586eb54129d3b9dd74b0287766af0bf3
Signed-off-by: James Simmons <jsimmons@infradead.org>
Reviewed-on: https://review.whamcloud.com/39388
Reviewed-by: Gian-Carlo DeFazio <defazio1@llnl.gov>
Tested-by: jenkins <devops@whamcloud.com>
Reviewed-by: Olaf Faaland-LLNL <faaland1@llnl.gov>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>