chore: make completion error outputs more descriptive

[shadychan]

Output description string of WC error status directly, which makes it easier for users to get the reasons (e.g. retry counter exceeded) without needing to refer to the codes.

---------------------------------------------------------------------------------------
                    RDMA_Write BW Test
 Dual-port       : OFF          Device         : mlx5_0
 Number of qps   : 1            Transport type : IB
 Connection type : RC           Using SRQ      : OFF
 PCIe relax order: ON           Lock-free      : OFF
 ibv_wr* API     : OFF          Using DDP      : OFF
 TX depth        : 128
 CQ Moderation   : 1
 Mtu             : 4096[B]
 Link type       : Ethernet
 GID index       : 0
 Max inline data : 0[B]
 rdma_cm QPs     : ON
 Data ex. method : rdma_cm
---------------------------------------------------------------------------------------
 local address: LID 0000 QPN 0x27d8 PSN 0x79f042
 GID: 00:00:00:00:00:00:00:00:00:00:255:255:192:168:01:39
 remote address: LID 0000 QPN 0x1c901 PSN 0x6726b1
 GID: 00:00:00:00:00:00:00:00:00:00:255:255:192:168:01:06
---------------------------------------------------------------------------------------
 #bytes     #iterations    BW peak[Gb/sec]    BW average[Gb/sec]   MsgRate[Mpps]
 65536      403504           0.00               42.31                0.080701
 65536      247166           0.00               25.92                0.049433
 65536      0           0.000000            0.000000            0.000000
 Completion with error at client
 Failed status-transport retry counter exceeded (12): wr_id 0 syndrom 0x0
 scnt=668523, ccnt=668523
 Error occurred while running infinitely! aborting ...

[sshaulnv]

Hi @shadychan, please rebase