Fixes #4284: Move r30752 to v1.7 branch (Rename poorly-named global: usnic_ticks ->)

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r30752 [[BR]]
Rename poorly-named global: usnic_ticks -> ompi_btl_usnic_ticks

cmr=v1.7.5:reviewer=dgoodell
Fixes #4286: Move r30760 to v1.7 branch (OSHMEM: Fixed race condition problem)

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r30760 [[BR]]
OSHMEM: Fixed race condition problem in example code. 
The problem was with oshmem ring code, which cycles a constant amout of data through all the processes.
When the program would expect the memory to change it did not explicitly warrent a recv() call, thus
counting on the memory region to hold the new value when in fact it could be set before or after the
check, causing slower BTLs to pass and faster ones to fail. The fix changes the logic to anticipate
the next message rather then the current one, which would be a mistake.
Patch applied to both C and fortran90 version of the example code.

reviewd by miked

cmr=v1.7.5:reviewer=ompi-rm1.7
Fixes #4287: Move r30762 to v1.7 branch (OSHMEM: various fixes)

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r30762 [[BR]]
OSHMEM: various fixes

1. fix in oshmem scoll component: basic algorithms should
   call basic collectives since their implementation
   incompatible with others (fca, hcoll).

2. Set OPAL_EVLOOP_ONCE flag ON for libevent in the case 
   of yoda smpl. Otherwise there is possible deadlock in 
   atomic_basic_lock call

fixed by Val, Igor, reviewed by Miked

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