Fixes #4212: Move r30527 to v1.7 branch (bcol/basesmuma: check the return code)

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r30527 [[BR]]
bcol/basesmuma: check the return code of bcol_basesmuma_smcm_allgather_connection.

Fixes a segmentation fault found by the bogus intercomm_create test.

cmr=v1.7.4:review=manjugv