LU-16081 lnet: Memory leak on adding existing interface

LU-16081 lnet: Memory leak on adding existing interface

In the function lnet_dyn_add_ni an lnet_ni structure is allocated.
In case of an error the function returns without freeing the memory of
the structure.
Added handling of possible lnet_net structure memory leaks.

Test-parameters: trivial testlist=sanity-lnet
Signed-off-by: Frank Sehr <fsehr@whamcloud.com>
Change-Id: I7544a9379093b99f77aaddb8d021b4a5bf221082
Reviewed-on: https://review.whamcloud.com/48173
Reviewed-by: Chris Horn <chris.horn@hpe.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Serguei Smirnov <ssmirnov@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Oleg Drokin <green@whamcloud.com>