UCT/IB/RDMACM/CM: fix stub functions of dummy iface

[evgeny-leksikov]

What

Fix stub functions of dummy iface

Why ?

CM lane is not able to communicate with put_bcopy and am_bcopy

How ?

replace ucs_empty_function_return_zero_int64 with ucs_empty_function_return_unsupported

[mellanox-github]

Mellanox CI: PASSED on 25 workers (click for details)

Note: the logs will be deleted after 26-Dec-2019

Agent/Stage	Status
_main	✔️ SUCCESS
hpc-arm-cavium-jenkins_W0	✔️ SUCCESS
hpc-arm-cavium-jenkins_W1	✔️ SUCCESS
hpc-arm-cavium-jenkins_W2	✔️ SUCCESS
hpc-arm-cavium-jenkins_W3	✔️ SUCCESS
hpc-arm-hwi-jenkins_W0	✔️ SUCCESS
hpc-arm-hwi-jenkins_W1	✔️ SUCCESS
hpc-arm-hwi-jenkins_W2	✔️ SUCCESS
hpc-arm-hwi-jenkins_W3	✔️ SUCCESS
hpc-test-node-gpu_W0	✔️ SUCCESS
hpc-test-node-gpu_W1	✔️ SUCCESS
hpc-test-node-gpu_W2	✔️ SUCCESS
hpc-test-node-gpu_W3	✔️ SUCCESS
hpc-test-node-legacy_W0	✔️ SUCCESS
hpc-test-node-legacy_W1	✔️ SUCCESS
hpc-test-node-legacy_W2	✔️ SUCCESS
hpc-test-node-legacy_W3	✔️ SUCCESS
hpc-test-node-new_W0	✔️ SUCCESS
hpc-test-node-new_W1	✔️ SUCCESS
hpc-test-node-new_W2	✔️ SUCCESS
hpc-test-node-new_W3	✔️ SUCCESS
r-vmb-ppc-jenkins_W0	✔️ SUCCESS
r-vmb-ppc-jenkins_W1	✔️ SUCCESS
r-vmb-ppc-jenkins_W2	✔️ SUCCESS
r-vmb-ppc-jenkins_W3	✔️ SUCCESS