Crash in verbs provider using FI_INJECT

[shefty]

I'm seeing the following crash running an updated version of fabtests:
#0 0x00007ffff7d97f0b in fi_ibv_send_iov_flags (ep=0x60f1a0,

wr=0x7fffffffe360, iov=0x7fffffffe430, desc=<value optimized out>, count=1, 
context=0x0, flags=167772160) at prov/verbs/src/fi_verbs.c:1332

#1 0x00007ffff7d98061 in fi_ibv_msg_ep_sendmsg (ep_fid=,

msg=<value optimized out>, flags=<value optimized out>)
at prov/verbs/src/fi_verbs.c:1362

#2 0x0000000000403678 in fi_sendmsg ()

at /usr/local/include/rdma/fi_endpoint.h:284

#3 ft_finalize () at common/shared.c:865
#4 0x000000000040189f in run (argc=,

argv=<value optimized out>) at pingpong/msg_pingpong.c:194

#5 main (argc=, argv=)

at pingpong/msg_pingpong.c:234

I believe that the issue is fi_ibv_set_sge_iov() is dereferencing desc, which is set to NULL since the FI_INJECT flag is set.

[shefty]

@a-ilango