Fixes #4350: Move r30962 to v1.7 branch (OSHMEM: scoll fix corner cases)

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r30962 [[BR]]
OSHMEM: scoll fix corner cases

- fix segv
- proper enable/disable and prio handling

fixed by Elena, reviewed by Igor/Mike

cmr=v1.7.5:reviewer=ompi-rm1.7
Fixes #4352: Move r30964 to v1.7 branch (bcol/ptpcoll: initialize all pointers in)

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r30964 [[BR]]
bcol/ptpcoll: initialize all pointers in the module to NULL to avoid possible
problems when the module is being destructed.

References #4331

cmr=v1.7.5:reviewer=manjugv
Fixes #4355: Move r30967, r30970 to v1.7 branch (osc/rdma: silence warning)

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r30967 [[BR]]
 Fix segmentation fault when osc_rdma is used with pml_cm: osc_rdma 
assumes the send request is derived from mca_pml_base_send_request_t,
but this is not true for pml cm, so we end up freeing invalid pointer.
 We cannot take the data pointer from the pml send request, so we pass 
the allocated buffer pointer in req_complete_cb_data, and put the 
osc_rdma_module pointer in that buffer as well.
 Previously, osc_pt2pt was used with pml_cm which didn't have this 
problem.

cmr=v1.7.5:reviewer=ompi-rm1.7


r30970 [[BR]]
osc/rdma: silence warning

cmr=v1.7.5:ticket=#4355
Fixes #4351: Move r30963 to v1.7 branch (coll/ml: fix bcast buffer size)

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r30963 [[BR]]
coll/ml: fix bcast buffer size calculation

cmr=v1.7.5:reviewer=manjugv