[ewg] ibdiagpath return code incorrect

[Edward Mascarenhas]

It appears that even on error ibdiagpath is returning zero but it
should return non-zero for error cases. Scripts that call ibdiagpath
can use the return code to take appropriate action.

Here is an example.

==================================================
service0: # ibdiagpath -i 1 -d 1,12
Loading IBDIAGPATH from: /usr/lib64/ibdiagpath1.2
-W- Topology file is not specified.
    Reports regarding cluster links will use direct routes.
Loading IBDM from: /usr/lib64/ibdm1.2
-I- Using port 1 as the local port
    (since that is the output port based on the provided direct route).

-I---------------------------------------------------
-I- Traversing the path from local to destination
-I---------------------------------------------------
-I- From: lid=0x000c guid=0x0002c90200291949 dev=25218 service0/P1
-I- To:   lid=0x001d guid=0x0800690000005264 dev=48438 Port=28


can't read "PATH(1)": no such element in array

service0:/tmp/src # echo $?
0
service0:/tmp/src #
================================================

Assuming this is a bug, I don't have a fix, but I'm hoping someone who
is more familiar with the ibdiagpath code will provide a fix.

Thanks,
Edward