Remove co_collectives.f90
Remove co_collectives.f90

* dev/co_collectives.f90: Remove, now that the compiler itself generates
  the calls to co_sum/co_min/co_max.

sourceryinstitute/opencoarrays,sourceryinstitute/opencoarrays,jerryd/opencoarrays,zbeekman/opencoarrays,jerryd/opencoarrays,zbeekman/opencoarrays,sourceryinstitute/opencoarrays,jerryd/opencoarrays,zbeekman/opencoarrays